They really should have. He wasn't as bad as Kusucka because Mutsuki was a bitch (Undead or not you don't get whipped by a girl) "He was being controlled by the Spider" my ass, he just got in the way. What was the difference between Tachibana sealing him and Mutsuki's sealing?
Did you even watch his story arc? And that bit about getting "whipped" by a girl all I can say to you about that statement is this :shakefist:sweat::redface2:
Like I've said before, Kenzaki is a real hero. When you make that kind of sacrifice to save a friend...