No, you very much can criticize something that is diverse because there are aspects outside of that. Like Concord.

You could even criticize how it’s diverse. If it’s done in an insensitive manner for example. Maybe they changed a character after they were established, (as a gay man myself I hate when they change a characters sexuality). Could complain that something is too sexual for the target audience(hint, gay couples existing and showing affection isn’t “sexual” when a straight couple can do it and no one bats an eye).

But if your criticism is the existence of diversity, you’re a racist bigot and you should be called out for that. There is zero valid criticism on the mere existence of someone different than you in media.