If you go in with that attitude, though, are you there to try to convert people to your side. Or are you only there to berate them and make yourself feel better for having done so?

That doesn’t mean you put up with bad faith engagement. That doesn’t mean you allow them to burden you with the emotional and mental weight of the argument. That they can watch the consequences without fear of it harming their self is exactly why you need to watch your language. They lose nothing staying where they are, you need to convince them to give up resources (mental, emotional, financial) of their own to take up your position.

So, don’t put up with bullshit, and you don’t have to be nice about it, but you do have to be patient of your goal is to actually convert people over. Not everyone’s role is to convert people, though, some people are only fighters. Just make sure the fighting is directed in the right places.