Is what he said wrong? Is his history relevant to the actual message he is communicating here? To me, it seems like the answers are "no" and "no".
Guy records a radio PSA saying "don't punch strangers in the nose". Later, it turns out that the guy has a history of punching strangers in the nose. Is the PSA wrong?
There's a way to write the comment that points out that Arrington's history here might be checkered. Unfortunately, the way you wrote your comment isn't that way, because it calls the message into question along with the messenger, and the message here seems valuable.
Guy records a radio PSA saying "don't punch strangers in the nose". Later, it turns out that the guy has a history of punching strangers in the nose. Is the PSA wrong?
There's a way to write the comment that points out that Arrington's history here might be checkered. Unfortunately, the way you wrote your comment isn't that way, because it calls the message into question along with the messenger, and the message here seems valuable.