For me it is, yes, thoroughly depressing but then, my upbringing in NI means and as my choice of degree subject indicstes that I consider politics very important. It's impossible for me to imagine my life without that interest, but if you plain aren't bothered, then yes, of course you will see things differently and not care to discuss it. And that's fine, for you.
Like the op though, what does bother me is when people say "no, we aren't discussing politics, because them's the rules". No, YOU aren't discussing politics, because you don't care to. I and whoever wants to, are discussing it and lucky for me, we do and always do so in a perfectly civilised way. If I thought it was going to be an uncivilised discussion, then obviously I would change the subject. But I would never then say politics is off the table as a subject. That isn't something I would do. I wouldn't go out of my way to censor all future conversations, because we once fell out over x, y or z.
Different if you don't naturally lean towards discussing politics with your friends or family, but honestly, even my granparents were very interested in politics (socialist; I am not really). We all had different views but we always discussed it, because we respected each others opinions, even if they weren't exactly the same.
This is all hypothetical anyway, because I've actually not had a member of the conversation police wade in mid chat to say "we aren't discussing politics here", except when I see it aimed at other people on SM. I just can't imagine it happening IRL. But you never know