There's more to it then just well...All of this and admit fully I am guilty of few minor ones (The IGN jokes primarily I've never been a big fan of them and that doesn't even stem from KH rather how they've treated other series I like.)
I actually enjoy seeing what other people think of the series, for example, you dislike Birth by Sleep? Cool, not my opinion but I can see why someone would dislike it and that's the same with Dream Drop Distance which in most cases I just generally dislike the whole Time Traveling thing. And then seeing people call me "OMG YOU ARE JUST STUPID." or "Wow you didn't even play the game." etc stupid comments like that make me facepalm.
But since most of those have been covered let's talk about another more dark part of the community considering KH3 is around it make just even get worse and that the shipping community... The shipping community in KH is like an iceberg with a tip the shipping community is on that tip constantly bending back and forth, back and forth you get the idea It can be stable and at times it can outright just toxicity and complaining about WHO'S SHIP is better AND OMG YOUR A HOMOPHOBE FOR NOT SHIPPING RIKU X SORA. etc Note that one is primarily for the Tumblr folks
The Final Fantasy stuff I agree with yes KH introduced me to Final Fantasy and I'm glad it did and while I am not the biggest fan of Turn based games I still enjoy them greatly, however, seeing people make stupid comments like "THE TURN BASED COMBAT GENRE IS DEAD." Have obviously never played a single Persona game in their life. On the flip side, however, I dislike people within the community that do nothing but complain, complain and complain about how much KH3 will suck and why 2.8 is garbage etc there is a difference between constructive criticism and whining about stuff because it doesn't hold your hand or fulfill every single wish. Most of these people are the ones who say they only liked KH1 and everything else is bad and when you ask them they usually respond with I DONT HAVE TO EXPLAIN WHY YOU IDIOT. Another thing is the people who get all sensitive about a minor thing happening and this is primarily directed to this forum itself and just certain people I've had interactions with they are few and rare I just generally don't talk with said, people, I have the people I enjoy talking to and most of em are pleasant people who I enjoy just having fun with or Roleplaying with. So yes I agree with this rant entirely and tbh I hope it makes awareness to people who may have unaware done a few of these things and hope it helps them realize that they only paint the community in a toxic image and that's not what the KH community is