There were entire Ekklesias that were 100% full of only converted uncircumcised Gentiles. Not even one Jew present. Gal 5:2 and Gal 6:13 proves that. Paul is warning Gentiles against Judaizers like you. In your case, you are judaizing Ethnic Cleansing.
No, really, there weren't. You're exaggerating and blowing Saul's Galatian letter out of proportion. That behavior reminds me of a Proverb:
6 Add thou not unto his words,
Lest he reprove thee, and thou be found a liar.
Prov. 30:6.
First, Saul didn't find the Jewish Church in the Galatian region. It was founded by Jewish Christians who returned home to this area after their experiences at the Feast of Harvest (Pentecost.)
Jews that were at the Feast returned to their homes and synagogues in Galatia and brought back an outline of Peter's sermon and their experiences with the Holy Spirit of Promise and testimony of Jesus as Israel's Messiah. I'm sure there were committed circumcised Gentile proselytes in these synagogues as well as uncircumcised devout committed Gentile God-Fearers in these synagogues but very few in number. Judaism was not a missionary religion and there were most likely more Gentile proselytes and God-Fearers in ouccupied Israel. Saul's letter to this region may have written ABOUT these groups but the gist of all his letters were written to his brethren Jewish Christians.
Although you're not honest with Scripture and your doctrine derives wholly from a Gentile mindset bias and persuasion these clues in his letter reveal a primarily Jewish audience:
Gal. 1:4 "our sins,."
Gal. 1:6-9 the "another gospel" he writes about is Judaism.
Gal. 1:13-14 "Jew's religion" twice referring to Judaism of which he was a Pharisee and a rabbi. "my equals" refers to the other "aged persons" or elders referring to his being a rabbi and Pharisee among other rabbi's and Pharisee's.
Gal. 1:15 "separate me from my mother's womb" is a clear referrence to Jeremiah 1:5 and only Jews would understand his reference to their prophet, Jeremiah.
Gal. 1:16 "heathen" is the Greek "ethnos" from which we get "ethnic." Saul mentions his being sent to non-Hebrews (Gentiles) by God.
Gal. 1:17-19 metioning the Jewish brethren, the apostles in Jerusalem. Peter and James are mentioned of whom the Jews would know about these two twenty years on than Gentiles would.
Gal. 1:20-24 Saul's prior reputation as a Christian hunter preceded him among the Jews since Saul was attacking what was at the time known as a Jewish sect among Judaism. Gentiles would not know this until much later but among Jews there were reports about this Christian hunter by word of mouth and Jew's did not 'hang out' with Gentiles as they were enemies. Gentiles lived and mingled with Gentiles and Jew's separated from these 'unclean' Gentiles. Remember the Roman centurion who was a devout God-Fearer, he knew Jesus couldn't go into a Gentile house but Jesus was determined to do so knowing he was a devout God-Fearer as He was sent to the lost sheep of the house of Israel and a God-Fearer was a ally of Israel. There was also a Roman centurion who built a synagogue for the Jews. A hard-core Gentile who was unfamiliar and not an ally of the Jews would not do such a thing as build anything for the Jews but most likely another Roman would destroy their synagogue.
Galatian 2 clearly addresses a Jewish audience. I'm not going to itemize all the references to Jewish history,m culture, religion, Abraham and Moses, and other clues that Saul was definitely writing to a Jewish audience in the Galatian region. There was no Gentile ascendency until after the destruction of the Jewish Temple about two decades later from the date of Saul's letter. It was a Jewish phenomenon that was taking place among the Jewish people and the Church that Christ was building was being populated by Jews, not Gentiles. Your bias to find anything in these letters written to Jewish Christians at their respective churches of a Gentile nature is founded on a Gentile mindset that refuses Israel their long-awaited Messiah and try to cast Jesus as a Gentile Messiah and the first century churches as being Gentile is in error. Everything taking place among the Jews with regard to Jesus Messiah had to do with the Jews since He was the fulfillment of covenant and prophecy and everything was of a Jewish nature and culture and religion. You are infected with a Gentile bias that causes you to see the covenants, Israel's Messiah, their history, their culture, their covenants, etc., as being Gentile-laced which it isn't. There was nothing in true, biblical Christianity that was Gentile until the Gentiles destroyed the Jewish nation, their cities, and their Temple in AD 70, and scattered the Jews away from their land even writing laws that prevented Jews from returning to Jerusalem which was completely destroyed. "Not one stone upon another" Jesus said. Remember? The destruction of Israel was widespread and total. Nothing remained. Rome was thorough in their acts of total devestation of the Jewish nation after several revolts and Roman deaths. An honest approach is seeing Saul's letters to Jewish Christians in the first century as Christianity was a Jewish sect among Judaism just as Sadducees and Phariseed and Essenes were sect in Israel. Until the destruction of the Jewish Temple everything taking place among the Jews had to do with their covenants and their prophecies about their Messiah and the new era they found themselves in with the advent of Yeshua and their Holy Spirit of Promise.
You can steal Israel's covenants and their Messiah but do it later and after the destruction of their Temple but not hijack it before then. It's completely dishonest that Gentiles do that. I am reminded of Catholicism which did the same thing in trying to trace their history into the first century when truthfully Roman Catholicism did not really begin to take shape until the fourth century and Emporer Constantine and the emporers that followed. Some popes claimed to stand in the shoes of Peter until one pope made the incredible claim that he stepped not into the shoes of the great fisherman (Peter) but into his actual FEET!
2 Indeed I, Paul, say to you that if you become circumcised, Christ will profit you nothing
13 For not even those who are circumcised keep the law, but they desire to have you circumcised that they may boast in your flesh.
That proves that the Church of Galatians did not have even one circumcised Jew. I have serious doubts if you ever read Galatians.
If there were no Jews in the Galatian region why does Saul use the possessive personal pronouns "we" "our" "ye" etc., in chapter 3? He also mentions Abraham and Jews being the rightful heirs of the Abrahamic Promises:
23 But before faith came,
we [Jews] were kept
under the law, shut up unto the faith which should afterwards be revealed.
24 Wherefore the law was
our [Jews] schoolmaster to bring
us [Jews] unto Christ, that
we [Jews] might be justified by faith.
25 But after that faith is come,
we [Jews] are no longer under a schoolmaster.
26 For
ye [Jews] are all the children of God by faith in Christ Jesus.
27 For as many of
you [Jews] as have been baptized into Christ have put on Christ.
28 There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for
ye [Jews] are all one in Christ Jesus.
29 And if
ye [Jews] be Christ’s, then are
ye [still Jews] Abraham’s seed, and heirs according to the promise.
Gal. 3:22–29.
Christianity was a Jewish sect within the Jewish religion. Originally called "the Way." And Saul's words were to Jewish Christians who were concerned about their standing in the Abrahamic Covenant now being followers of their Messiah. But Saul puts them at ease with his words in chapter 3.
Until the destruction of the Jesish Temple everything taking place among the Jews was in accordance with their covenants and the prophecies of their prophets and the patriarchs of their people.
Gentiles did not steal true, biblical Christianity until after the destruction of their Temple.
Much later.