Not saying I agree with the call, but this is my understanding of why they called it that way.
The way that the rule is written,
any contact to the groin area that is not "clearly accidental" is an automatic Flagrant 2 foul. Of course, "clearly accidental" is an absurd and undefinable standard. It doesn't matter if it was "incidental" contact, if they deem that it wasn't "clearly accidental" then they have to call it, and the only thing they can call is a Flagrant 2. In this case, I guess they decided that because Baker lowered his shoulder, it wasn't "clearly accidental" - even if it's pretty clear that he didn't mean to elbow the guy in the nuts. He did purposely lower his shoulder and make the contact. So they can say that it WAS incidental contact, but NOT accidental contact because what he did was an intentional move because of the pressure.
I think this is similar to the "forcible contact to the head or neck area" targeting call in football. It doesn't matter if there was intent to commit a targeting foul - if there is forcible contact to the head or neck area, it limits what the officials can call on the play because that contact was made. The only difference here is the ridiculous "clearly accidental" standard.
I hope this prompts a rewrite of the rule because it is poorly written and applies a dumb standard the way it is currently instituted.
https://twitter.com/GeneSteratore/status/1903827222147821697