Obviously I don't live inside Kiell's head, but I got the impression he wasn't so much outraged not to have won as by the fact that MBB did win.
I reckon that, if one of the other nominees had won instead, he would have accepted it with good grace.
A bit like, in an art competition, you'd be disappointed but accepting for your entry to lose to another beautiful painting or sculpture; but you'd be so insulted if some clown gaffer-taping a banana to a wall was judged better than you.