This.
The fan criticism of Warren and X together was ALWAYS about how poorly established and OOC the behavior was. By contrast, the teasing between X and Tyke was actually quite sweet and builds on where both characters are coming from. It's possible to actually SEE why Laura might like someone like Scott. Warren, by contrast, was thrown into the mix without any prior interaction at all. Just for some reason all of the sudden despite having NEVER really talked with her at all he's suddenly making a play for her during the second Brotherhood arc. THAT has always been the problem. Bendis chalking it up to "Oh, they're just too different," demonstrates either just how out of touch he actually is with the fanbase, or that he willfully ignores what he doesn't want to hear.
Criticism about X and Warren being too different can be waved off like it's the READER'S problem and they just don't get it, which is essentially what he did. Criticism that the relationship was poorly developed and out of character is a criticism against Bendis as a WRITER. That's not something he can spin so easily.
And I'm sure had Bendis done with Pixie what he's done with X, you'd probably have a different opinion.