Maybe I'm missing something, but to prove his point MP just needs to up the ante. If ICBIT is a bucket shop it would be out of business (or MP will be out of his money, hehe).
So basically, here's a bucket shop working suckers out of a few bitcoins a day. MP comes by, risks a few hundred BTC of his own money, establishes some points. Your retort is that "he's a pussy" because he's not dumping more money into the scam.
Are you in any way involved?