He's just defending himself against statements that don't need to be defended...
The fact that some people want zombies to be taken back a notch and stumble around like they should instead of running around like psychos and even learning how to shoot guns (land of the dead = biggest load of garbage) and that he is defending his ideas against that... it is just ridiculous and kind of shows a dumb side of him. He doesn't need to defend himself or his idea against that statement/suggestion because he has marketed them as zombies all along. THEY ARE ZOMBIES, so what if they run damnit, they are still zombies, he must be full of himself on his own ideas if he really thinks that arguing his notion about his zombies not being zombies then I sense FAIL.
Yeah, he has the right to defend his ideas and yes they are infected and could be put into a less-than-zombie category... BUT WHO CARES MAN, he marketed them as such and damnit the whole thing makes it out as though they are zombies, infection or otherwise.