What bothers me about "incompatibility at the Planck scale" is that the Planck scale is a completely unknown and untested regime of physics. I personally don't care at all what any theory says will happen at the Planck scale-- it's irrelevant whether or not they are "compatible" at a completely untested energy scale. Even if they made exactly the same predictions at that scale, I wouldn't pay more than passing attention to those predictions. In the complete absence of experimental verification, as exists at that scale, any theory is purely amusement for an idle mind, and is virtually guaranteed to be wrong. Must we learn that same lesson over and over?