Men think being immoral is okay since girls are immoral.

Nazis think censorship is okay since Communists hate free speech.

White people think being immoral is okay since Jews and blacks are immoral.

The problem with doing wrong because others are immoral is that everybody becomes immoral and society breaks down. Two wrongs don't make a right. No one can take the moral high ground if everyone is unethical.

Someone needs to lead by example.

Being moral when everybody is corrupt might lead to being treated like a rug, but you have to live with yourself. Even atheists have consciences.