Proves too much.
"Then he asked me was I keeping all the other commandments, living a righteous life, insinuating that if I was not I could not possibly be keeping the 7th commandments because the bible makes it clear if you are guilty of one then you are guilty of breaking all the commandments, and if that is the case what is the use of the 7th commandment but to condemn."
That logic "proves" that we can commit adultery, murder, and steal.