The fact that God can do something is not a justification for Him doing it. The fact that God can damn everyone without a reason is not an argument for justifying teaching that he does as in the Calvinist doctrine of double predestination. All that He can do is restricted by the standard that God values most which is His love. If it will violate love, God will not and cannot do it for that would be contrary to His nature and character as a loving God. And if it will violate love then it is not right. God cannot make it right by doing it just because He is sovereign. If God does it just because He is sovereign then He would not be God but something else.
First a bit more on your assertion that God's holiness and His love are primary attributes to which others, such as justice for example as you claim in your penal substitution arguments, is secondary. Justice is contained in holiness as is love. Absolute justice is part and parcel of being holy. His holiness cannot allow unholiness in His presence. That is why the high priest had to first offer sacrifices before entering the Holy of Holies. And why one he could enter and only once a year. And why Jesus had to pay with His life as the sacrifice to end all sacrifices, thereby allowing those who are in Him through faith to come before His very throne.
And here, as I said before in the thread you closed, is the inaccurate depiction of Calvinism as your premise for refuting it. Calvinism does not say that God's justice has anything to do with doing something because He can. That is simply how you choose to portray it and maybe even believe, but it does not. It is also your premise for arriving at a different doctrine of God. So neither one hold any water at all. It doesn't say God can damn everyone
without a reason so that is a logical fallacy used as an valid argument also. It is merely how you choose to portray it, and if you actually believe that, you have been shown where you are mistaken. I won't take up the space here to repeat myself in vain.
When you say that God cannot do it for that would be contrary to His nature and character as a loving God then I challenge you to explain how following fit your definition of love.
God striking dead on the spot men who touched what was holy.
Sending men into other nations to kill the people and take their wealth.
Sending the king of Assyria to execute His judgment of Israel, removing them from the promised land and scattering them into other lands.
Sending Babylong to execute judgement on Judah, destroy the temple, giving its gold and silver to His enemies, and walls and gates and scattering the inhabitants abroad away from the promised land.
Sending His own Son to the cross.
Destroying all the wicked in the land.
God does nothing just because He is sovereign and Calvinism teaches no such thing.