As a disabled veteran, I get it.
We don't know that Mitch is disabled first of all. As far as I know, the Republicans are acting like his health is normal.
Second, brain trauma is a serious injury and should not be the target of jokes, I agree
But if your job is public speaking and you make a gaff, like President Biden does, it's always been fair game. Disabled folks like myself, can separate themselves from the criticism of McConnell.