Well, I see two things with that sort of email.
First, he was just trash-talking, and chances are, since was only one email, the guy was probably just having fun. Once email isn't SPAM. It just may have been in bad taste.
Second, the use of language on his part seems very poor, to say the least. This is a family game, and you could be 10 years old for all he know. Maybe emails need a language filter? Just a thought.
But I agree that blocking emails is a good suggestion. This was probably a bad message, and hopefully one that the sender will feel bad about if this was pointed out to him. However, I'm sure there are worse out emails that can and have been sent, and just being able to block certain senders who routinely have bad judgment, and you just don't want to get any messages from them.
This was an excellent thing to bring up on the Suggestion board, IMHO.
Don't ask what sort of Chunks they are, you probably don't want to know. Blowing Chunks since Season 4!