How long did it take Corbin to grow enough balls to bench Bell? I don't see Howard taking it to the extreme of hopping off the team bus (which still didn't lose Bell minutes) so I see Corbin feeling guilty about letting an "experienced vet" who signed here to get minutes not get playing time.
I see that as a rationalization for Corbin having a different opinion on the overall contributions of Howard than many members of this board have. Corbin's seen a lot of coaches get fired for losing. I don't believe for a moment he would chance losing more games out of guilt over who signed where.