I'm suggesting that joking about a person's death needs to be considered against the nature of that death and the current environment.
It's very likely that the family of that kid will happen upon this forum and that post in the next little while, and I think as a community it would be nice if they weren't met with the same idiotic comments that they'll find on the bodybuilding site.
It's the same thing as making jokes about 9/11 victims on 9/12, but there's no hard and fast rule. Such is the case with pretty much every social nicety.
More to the heart of much great humour is timing.