Worth noting that Twitch usually doesn't make a statement about bans / ban reasons. This is Finegold's claim, and he is far from a neutral party.
Also the specific issue was reading the email address, not the message. This, naturally, invites chat to send messages to that address. Regardless of intent, this is a very reasonable expectation to have. If the email is not a troll, that amounts to inviting a horde of people to send nasty messages to a suicidal person.
He read out a nasty email someone sent him on the stream apparently, his ban should expire shortly if it hasn't already.