I think if a public figure kills himself and someone else because of the incredibly selfish, disgusting, and dangerous decision to drink and drive, then it's not inherently inappropriate to comment on it. Just like if someone died in a drug overdose, it can be a good jumping off point for reminding people (particularly their young fans) of how dangerous drug use is.
I also think the use of the J-A word was not inherently wrong - it's a reasonable reference to me.
But I do think you have to consider the timing after the death, the medium of your message, and the tone of your message. I completely completely agree with what he said, and if we'd been hanging out together, watching the news, and he made that comment, I would have given him my total stamp of approval. But a semi-joking statement, over twitter, immediately after the death - in combination, those caused his statement to cross the line for me.