There is no gatekeeping

Definitionally there is, because you called Fandom wikis "non-genuine wikis". "genuine wikis provide a much nicer user experience than Fandom wikis". That's quintessential gatekeeping, and it's incorrect gatekeeping at that, because they provably are.

just a statement of a preference, as a user.

We both agree here. You are correct to want to use platforms other than Fandom. Fandom sucks for editors, sucks for readers, and sucks for fan communities; I could write an essay explaining why. I understand the sentiment behind the meme completely; it's the way it arrives at the sentiment that's totally nonsensical. You've made no coherent point and spread misinformation. You don't have to make a point to express your opinion, but it's clear you tried to.