PUA techniques in general are about making each encounter sexual as quickly as possible and abandoning each conversation as soon as your realize sex is not going to happen. If your goal is to avoid going home alone, this makes sense. Even if PUA techniques were actively offputting (hint: many are) to the point where they halved your chance of getting lucky, if they were three times faster you would get 50% more casual sex. That doesn't mean it would be the optimal approach if you had your heart set on one particular woman. And, even if you get laid, you probably haven't presented yourself as a desirable long-term partner.
When it comes to negging specifically, there are enough fucked up, insecure women in the world that I'm sure veiled insults will get you into *somebodies* pants. And starting out by demeaning your target will quickly sort out the people with spines, leaving you only the easily manipulated to spend time on. So I can see this being a way to get laid. But I'm pretty sure that women *in general* don't like to be insulted, and women you want to date almost never do.