After reading on this a little, I still think that this should become forbidden (which obviously wouldn't stop people from doing this, but it would at least act as a deterrent).
With regular stock trading I can only buy shares and hope that the price goes up (as a regular joe I can't realistically influence this, because I'm not crazy neither powerful nor well connected enough).
But if I bet that the price will go down and I'm fairly crazy, I can go out and influence the outcome. For example, I could just stalk and shoot Elon Musk, which would totally bring down Tesla's and SpaceX's share prices and I'd make serious money on that?
Crazy that this entirely legitimate, especially in today's world.
But I guess finance industry just doesn't care.