I think it's fine to decline to engage on a topic. There's a time and a place to talk about things and a lot of online spaces aren't the place for certain discussions. A few years ago, for reasons I talked about
here, I mostly stopped posting about politics online. If someone is going to lose their shit at you because you don't engage then they probably weren't going to be having a good faith discussion with you anyway.
I find that a good thing to remember is that you can't control how people react, that's up to them. The only thing that's in your control is what you do and so choosing to not engage is totally fine. You don't owe your time to strangers online.
I'm still open to having those discussions in other situations and think it's important to talk to people who hold different opinions than you so that you can have a broad perspective. But when I look around at the political discussions taking place online and see people labelling those who disagree with them as mentally ill, I can't say I feel like I'm missing out by not taking part.
I really do think that most people are generally decent and reasonable and that we have more in common with each other than we have differences. So, when it comes to somewhere like here I'd rather spend my time shooting the shit with someone and sharing things that make us laugh.