Peter violated NON SCRIPTURAL MAN MADE LAWS. I don't know why you can't understand the difference.
I said to Peter before them all, If you, being a Jew, live in the manner of Gentiles and not as the Jews, why do you compel Gentiles to live as Jews? 15 We who are Jews by nature, and not sinners of the Gentiles. (Gal. 2:14,15)
Peter was living like a gentile. No problem -- until he turned into a hypocrite.