A parade shooting is bad, very bad, but is still tame compared to the sorts of things to which website moderators are exposed on a daily/hourly basis. Footage of people being shot is actually allowed on many platforms. Just think of all the war footage that is so common these days. The dark stuff that moderators see is way way worse.
It absolutely does not look the same. You instinctively know that what you see is just acting. I somehow don't believe that you have seen a real video of a person getting shot or beheaded or sucked into a lathe. Seeing a life getting wiped out is emotionally completely different because that's more than a picture you are emotionally processing. It looks only the same if you have zero empathy or are a psychopath.
