The reason he cant talk to Freddie/Halfwit is because his little brain cant comprehend anything remotely intelligent. He takes everything at face value and doesnt try and understand what someone is saying. He just interprets things one way and one way only and thats it. He's a dick.
Posted by DJG
That's exactly it! That's why whenever Freddie asks him why he's annoyed by him, Kris never gives him an answer and just says "oh you asking me that makes me more annoyed"- he's such an idiot- and Freddie shows him up as even more of one- which he knows!