Oh, please.
These videos rarely, if ever, show anyone actually being shot, it's generally blurred or something, just as this one is.
If some do actually see something like that, it's because they watch to see/be outraged by reality and not hide from it, and has nothing to do with enjoying watching someone be killed.
They watch because they hate it, want to feel the full impact of it, and don't want to forget it, not because they enjoy it. If one can't handle it, then don't watch it, but that making them better than others is far from the truth.