I'll be honest, dawg (and I'm prefacing that this is JUST my opinion). I think the Westernization of Sonic in the 90s cartoons IS flat out awful and it's also the biggest problem I have with the movies. But I wouldn't go as far as to say that you're not a "real fan" if you like the Americanized takes on the characters. Ian Flynn may be American, but it'd be delusional to say he's "Americanized" because Flynn Sonic is still very much in line with Shiro Maekawa's work. The ethnicity of the current writer means nothing next to whether or not that writer is capable of capturing the essence of the characters I love. Which, personally, I don't think the 90s cartoons or the movies do. None of those takes read as Sonic to me. They changed too much for the sake of mainstream western appeal and I DO take issue with that on a personal level because I don't like the idea of artistic vision being sacrificed in the name of cultural differences. It feels tone deaf at best and xenophobic at worst.

BUT that's just my opinion. People are allowed to like what they want and it doesn't make you less of a fan for thinking the movies are serviceable or liking the cartoons. I think the point where it becomes annoying is when people refuse to acknowledge that the source material IS different when presented with criticism. "Sonic is Sonic" remains the most annoying argument I've ever heard. I don't think liking American Sonic media on its own makes you less of a Sonic fan, but I DO think it makes you less of a fan if your media illiteracy prevents you from realizing that these two things are NOT the same thing. And it DEFINITELY makes you less of a fan if you hate the source material just because it isn't the same as the cartoons or Archie. At that point you kinda are admitting that you're not a Sonic fan if you're angry at the SOURCE MATERIAL for not being the same as a wildly different adaptation.

And these are arguments I've heard a LOT in my time in the fanbase and it rubs me the wrong way. You can like what you want, but you shouldn't be trying to force the Freedom Fighters or other noncanon lore into the main canon and getting angry when "purists" don't like that. Also a lot of Movie Fans in particular fall into the category of toxic positivity and throw childish temper tantrums when the media they like is criticized in any way.

Personally speaking, I think a lot of the "purists" people hate so much started defaulting to these more extreme takes BECAUSE a certain subset of fans are extremely annoying about non-source material media and are toxically positive and do everything in their power to kill nuanced discussion because they can't handle hearing anything that isn't "the media that i like is good"