Edited for legibility
Welcome to politcal memes!
These are our rules:
Be civil
Jokes are okay, but don’t intentionally harass or disturb any member of our community. Sexism, racism and bigotry are not allowed. Good faith argumentation only. No posts discouraging people to vote or shaming people for voting.
No misinformation
Don’t post any intentional misinformation. When asked by mods, provide sources for any claims you make.
Posts should be memes
Random pictures do not qualify as memes. Relevance to politics is required.
No bots, spam or self-promotion
Follow instance rules, ask for your bot to be allowed on this community.
Why exactly? Catching trolls is much easier on popular sites like the ones you listed. Sure, there are more of them, but also more of them are constantly flagged. Fediverse has no such overarching moderation, as you well know.
You don't see how that's a massive advantage?
I hope you don't need another reply to understand, you'll have to ask someone else.