It's not about being a doormat either: if someone is harming people, then I should do what I would want other people to do for me: fucking fight the assholes doing the harm.
That's "doing unto others as you would have them do to you."
I'm not religious anymore, but I do find the teachings of Jesus still have a lot of relevance to me. The man was preaching about revolutionary change & creating a world where no one is lowly & oppressed.