Yeah at large there's more to it, but when you really get down to it as far as Smash goes there aren't really even that many viable platforming characters people could be alluding to. Crash, Rayman and Tails / Eggman really. The latter two pop up now and again but a lot of those obnoxious platformer vs JRPG smash tweets continue to use Crash as the figurehead.
I feel bad for the Crash fans who get caught in that crossfire because stuff like that invites even further conflict around the character.
This is what I recently said. There aren't really that many popular platformer characters left outside of Nintendo. So the available options will be smaller unless we start talking about the likes of Yooka Layle.
This isn't really the case for JRPGs and other genres, specially with Ultimate, which has basically opened the floodgates for a lot of series. Before people would have laughed at you if you suggested a Persona character.
And I feel bad for Crash as well, because he's one of my MWs. But even if I know I shouldn't, and that these people are a minority, I'm starting to kinda despise the Crash fanbase because of things like this.
I remember I was following a K. Rool support account on Twitter that seemed nice until Byleth got in and hoo boy. So I don't know if some platformer fans are legit pissed because they are realizing that now platformer characters aren't as likely as before for multiple reasons, so they kinda concentrate their discontent against JRPG/anime characters because they're an easy target thanks to Fire Emblem and the classic "anime bad".
I remember when Mega Man “died” and people blamed Capcom for killing the franchise, meanwhile it has been in decline because people were getting burned out of annualized releases and spin-offs. Turns out, it needed a hiatus.
Seriously. Maybe the hiatus was very long but back then there was a LOT of Mega Man games releasing close to each other. Granted, each subseries kinda appealed to different people, but it definitely was a problem in the long run.
It doesn't help that with the years, making videogames isn't as cheap as before, plus they now usually take more time to create. Once a game needs more benefits to justify sequels, you will start to think more carefully about what you should actually develop and therefore, less ideas will be greenlighted.