The fact that a company would take that stance is proof enough that they can't be trusted with personal information. Honest companies don't act in that way.
They posted and communicated their Dwolla AML (need photo id to use Dwolla) policy. Ya, it sucks, sorry you weren't aware of it. In addition, the Mt. Gox terms of service say they can require ID at any time for any reason.
But they aren't going too change because there is a lot of whining on the BitcoinTalk forum.
There are several other exchanges which can be used nearly as easily as Mt. Gox. Next time you want to send funds to an exchange, don't make the same mistake, ok?