Gents, the rule is the rule! If you're dozy enough as a batsman to get caught out of your crease, then you haven't got anywhere to look but at yourself. Not to be applauded maybe, but don't get angry at a player for playing to the rules. That's what the rules are there for after all.
Also, seriously what does him not going through his action have to do with it? If you see the bowler slowing down and not bowling, you don't head on off out of your crease, you stop. The bowler actually has to slow down and not go through his action in order to mankad, what else is he supposed to do?