@John2374no, two wrongs don't make a right, but if someone is being polite, I'm not going to be rude to them even if I think they are wrong. I can tell them I disagree without having to be rude.
If someone is being continually rude, offensive and doesn't respond to polite advice (such as the guy @Sarah977 was responding to), then sometimes they need a stronger statement to help them wake up and smell that coffee, but they must have already crossed a certain line by that point. I don't think that is hypocracy, it's judging things on a case by case basis, which in my opinion is logical.
A guy who is slightly tipsy walks into a bar at closing time and tries to order a drink. He is politely told, no, sorry, we're closing now. He is disappointed, maybe asks again nicely, even tries some charm and humour. It doesn't work, so he accepts the judgement and stumbles out humming a tune.
A guy who is seriously drunk crawls into a bar, knocking over furniture and shoving people out of the way and demands a drink at the top of his voice. He's politely told, no, sorry, we're closing. He proceeds to scream, shout and hurl profanities at the staff and other customers. He starts throwing chairs. He threatens violence. Do you then react to this guy in the same way as tipsy guy number one? No, you need to be firmer. You tell him to leave immediately or you will call the police. You will probably need to raise your voice. You call security. Security will physically remove him from the premises, using force if necessary.
That is not hypocrisy. It's common sense.
A.K.A. pick your battles.