We all know the root of this outrage–it's the result of someone taking a tragic event, and not just making fun of it–but celebrating it. Or on a greater level, using it for monetary gain and entertainment. Messing with fragile human decency and all that good shit. And then on TOP of all that, there's the whole argument that goes “well if you're gonna do it, at least make it funny.” And the humor, although subjective, could definitely be considered relatively weak.
Was this offensive? Probably–particularly given the fact that the way the sketch was framed, it seemed like Jeselnik was attacking this one guy in particular. The end of the sketch reveals that he's using Mr. Strange as a vehicle for a larger argument (we're a lot worse to sharks than sharks are to us), but that message doesn't necessarily come across crystal clear.
That said, the show is also called the Jeselnik Offensive. As in, OFFENSIVE. Yes he may have crossed the line here, but that seems to be the entire point of having this show. The real lesson here is that if you're gonna offend people, the consequences of being unfunny are just a lot worse. Don't hate the player (Jeselnik), hate the human condition for liking “offensive,” over the top shit that gets ratings and an entire television show. It's just that when he bombs, it's a bigger explosion.