I'm going to offer an alternative interpretation which equally could be true: These people are idiots. They're just insensitive and unaware and have a retarded sense of humour. It's of a kind with 9/11 and Princess Diana and Lockerbie jokes. When I was at school, I remember a lot of sick and tasteless jokes - jokes about "What do you say to a woman with two black eyes", dead baby jokes, racist jokes, "What's the difference between a Mercades and a Ford Escort" and so on. All mixed in with jokes about Skodas, sheepshaggers and Essex girls. I think and am confident that in the vast majority of cases those children grew up to stop making those jokes and would now find them tasteless because they were never actually that racist or sexist. They were just doing the dumb, blind, boundary-teasing and thoughtless behaviour that children do. Just the same as I think there's a high chance one of these muppets, after a year of continual Grenfell coverage thought it would be a laugh to turn the bonfire into Grenfell tower. Not because of a sick pleasure derived from re-enactment. But because they, quite literally, have a retarded sense of humour like a kid of 15.
Which ain't great. But is different to getting off to people's deaths.