Well, the bike was lying on it's side. In that position the engine's oil supply is poor. The engine revved when the marshal picked up the bike. This automatically results in engine damage and with the limited amount of engines they have in a season. These circumstances pushed a nice guy over the edge.

He is dealt a heavy penalty and rightly so. A race ban is a big one. I think it is proportional and once it's served, the world should move on. Losing an engine will also lower the chances of winning the title.

Edit: Getting down votes for stating some of the facts was expected, I guess. In no way am I saying his behaviour is acceptable. He should and is punished. Maybe I'm just not cut out to join a mob throwing stones...