My son is 11, too, and didn't skip, so he's in 6th.
He read an article about the Syrian gas attacks and the many deaths of children last week in Social Studies. It was from the adult Time magazine. (In his school the highest ability kids read adult material and average kids read abridged "kid" versions.)
So I don't think the skip has anything to do with what he's exposed to in middle school SS. My son had to read the articles, then write his responses, which lead to some good discussions.
We stopped shielding our kids from most news by 5th grade. There are still things we mute on the morning news, but mostly, we let them know-- and they're interested. My 6th grader watched the news report this morning about the mass shooting at the ship yard. And my 7yo knows about it, too.
But regarding the falling man video-- I would contact the principal about it. I've seen that video and it is deeply disturbing and overwhelmingly sad. It's one thing to read about people jumping to their deaths and it's another to have to watch it. I don't think that's appropriate content for middle schoolers at all.
