Yes, the old Bitcoin community. But as you may have noticed, bitcoin got a lot of attention over the past year, and probably drew in a lot of users who weren't on that forum 3 or 4 years ago. All those mass media reports weren't immediately followed by warnings from the community to stay away from MtGox, so a lot of new Bitcoin users probably ended up at the biggest (and therefore presumably the most professional and reliable) exchange.

How could MtGox have been so big if everybody already knew for years that it was crap? The community failed to inform the new users about this very real danger.