[rayiner]

You're right, there is no mens rea, and that's why I think prosecuting the kid is massively stupid as well as wrong. But I just don't think it's a "thought crime." He didn't just have this thought, or say it in private, or even make a private aside to a friend. He posted it on Facebook where some uptight lady in Canada read it.

It's really easy to forget in Facebook, especially commenting on peoples' wall posts, that what you're doing is putting a statement in writing readable by potentially hundreds of people, not making a private comment directly to your friend. If he had said it to his friend in the lady's presence, and got prosecuted for that, it still would have been wrong to prosecute him, but I don't think anybody would be calling it a "thought crime."