The market intervention that people are demanding is only possible because Mt Gox is a centralized exchange. Had this been a hack of a pure BitCoin client, it would have been even worse, because the theft would have been irreversible.

If the community wants rollbacks when transactions aren't "fair," what's the point of BitCoin again?

Rolling back centralized trades is entirely different from rolling back a house burglary.

Right. It's clear that this is not a problem with Bitcoin itself, but a problem with an institution built on top of it. If Mt Gox fails, other trading platforms could emerge to take its place.

Likewise the freedom from government intervention that is the point of Bitcoin does not ensure freedom from government intervention in trading platforms built upon it.

Not that I don't expect problems to emerge with Bitcoin itself...

Out of curiosity, how big is Mt. Gox compared to the other bitcoin exchanges?

http://www.bitcoincharts.com lists the daily trading volume of various exchanges. I think the numbers for Mt. Gox represent the volume before things went sour, so based on that, Mt. Gox sees almost 30 times the volume of the next largest exchange.

MtGox has about 90% of the bitcoin change market.

I'm probably thinking of something different - but wasn't it clear in the bitcoin protocol itself that if a single actor controlled a majority percentage of the bitcoins out there, the model falls apart and is at risk?

Sorry, we have our wires crossed. You can still transfer bitcoins from one person to the other. An exchange is a website that allows you convert bitcoins in USD. MtGox controlled about 90% of the BTC↔USD conversions.