Bear in mind that Anonymous (or whoever the group is) is supposedly trying to get some attention over this. There are plenty of XJWs who are cheering them on and trying to support their efforts to get attention over this. That could be someone's motivation for sending that message out. Maybe they're hoping it will make the news that Anonymous has broken into Hushmail and the news will then mention the WTS pedo cases in the message?
I'm honestly not sure about the whole Anonymous story. I will reserve judgment until something actually gets released.
What Isaac said above makes a great deal of sense. I have had great reservations about the whole Anonymous thing from the git-go.