Take this post for example: https://www.reddit.com/r/northernireland/comments/1ll6ocg/see_it_say_it_censored_kneecap_is_not_the_story/
Speaking from experience, people in Ireland are overwhelmingly pro-palestine.
There is this user in the comments: https://www.reddit.com/user/EntireCourage308/
Its a nearly year-old account, it started posting about a month ago, it made some innoculous posts, then pivoted to posting far-right misinformation in the r/northernireland subreddit.
There’s loads of other accounts just like it.
It really isn’t, even on my instance used by like… 3 or 4 actual people so far, I have had more than enough spam accounts - and those were relatively harmless. Support the server admins and mods of the servers you are on/communities you are in, if able, they are the ones who are engaged in cleaning up incursions like it. Oh, and report things.
For what it’s worth, I do believe the Fediverse has higher resilience, thanks to a different culture, decentralised nature (with helpful platforms like Fediseer) and a lack of the “we just need numbers as big as possible for our investors to be satisfied”-incentive to tolerate anything that looks like engagement.