I think you're entitled to be as obsessional as you like, but you might find you're on your own with whatever it is you're pursuing, because the chances of what you're interested in being very interesting to anybody else are probably quite small. But if so, it's a shame they have to insult you just for trying to share it, especially if it's written stuff online where they can just scroll past it without feeling they're being rude. A bit of courtesy costs nothing.
I'm pretty obsessional myself, and I get a lot of fun out of it, but I rarely share it with other people these days. I've noticed they get bored and frustrated with it, and I've felt the same when other people have tried to talk to me about what they're interested in, if they don't give me the chance to redirect the conversation onto something else. I used to assume that if something fascinated me then it was a fascinating thing, therefore other people would also be fascinated with it, but I began to realise that people generally are pretty much only into their own individual interests, though there are exceptions.