Nah man. I think you're normal for not liking that. And I suppose in part you can take some of it personal. It's like, guys who actually train, even if you don't fight MMA, you have an idea of how tough it is. And you know how damn good you have to be to get to the UFC level. So you know that a couch fighter/internet warrior is being disrespectful. So if they're disrespectful to the elite, they're being disrespectful to nearly every other practitioner that can't even come close to beating them. It's insulting.
I mean, calling it objectively is fine. But calling guys has beens or washed up? That's just rude. That's disrespectful.
Should you let it get to you? No. Do you have the right to get angry? Sure.