Some black men allow their white girlfriends say "nigga."
And some people think cucumbers taste better pickled.
But that's essentially your post. And just a "hunch" that you have.

But, most things can be made fun of if done from angles that aren't demeaning, that aren't trying to make the unnacceptable accepted, that aren't contributing to the oppression of marginalized folks, that aren't punching down.
Dave was punching down.
And no one said they were "protected"
What was said is that Dave makes homophobic and transphobic jokes/statements.
That's not even remotely the same as saying "homosexuals and transpeople are off limits as subject matter"