You are welcome to judge from behind the monitor but if you actually went out and looked at reality, you'd realize there is nothing magical about negs and that
negs themselves won't get you a girl--whether emotionally damaged or not. It could in certain cases help you increase attraction a wee bit. In that sense, it isn't much different than tips we read about pitching to VCs etc.
I guess the thing that people don't like about it is the part where you insult people you don't know for selfish reasons? I mean maybe that's part of it?
That's a fair point. To that I would say once you lift the curtains and take a peek, you will find many different school of thoughts within this. Some of the most famous personalities and ideas about PUAs in the mainstream isn't even very popular inside the PUA community.
On the other hand, there are entire "systems" that are premised on being dead honest about your intention.