I'm pretty sure you can't arrest someone because of a petition. He hasn't done anything wrong. It's called freedom of speech.
I wouldn't waste any time getting upset about it. People have said worse about MCR and they won't stop. It used to all be Marilyn Manson's fault, now they have found a new artist to point the blame on instead of taking credit for being shitty parents and raising kids capable of murder.
Ignorant. Ugh.