Because it is, as I have said, magical thinking bullshit that damages people, especially people with conditions like OCD or Generalised Anxiety Disorder. It hurts people. If you want to reblog things, nobody is stopping you. But posts that are deliberately phrased to make people feel powerless if they choose to not reblog them are never helpful. And posts that trap people into patterns of superstitious, compulsive actions can ruin lives. I know that sounds like an exaggeration, but some people already can’t leave their house without rituals and compulsions that their brain tells them they must complete or people will be hurt or die. Reblogging a post that has no purpose, that is purely a superstition or a guilt trip, helps no one, makes you more likely to compulsively reblog posts like it in the future, and exposes people who follow you to perpetuate the same cycle of behaviour. A blog post cannot hurt your mother. By reblogging it, you’re acting as if it has a power it literally does not have, and you’re spreading it, like a virus, through the internet. It’s a chain letter, and like a chain letter, the only power it has is the power to spread unhappiness, and it only spreads through you. That’s the point I’m making. You never have to reblog something. It literally has no power. But you do.