I think it's because they're fun and relatable to dudes, even if they're girlish.
Then they believe their own lies, and really get a kick out of making people react. If you remain cool, calm and collected it's no good. If you get worked up it's no good.
They just keep on *****ing and *****ing until one day you tell them what's going on and the relationship is ruined.
TBH I've met guys with the same type of personality disorder. I met a guy once and told him: "dude you seem to want other people to submit themselves to you", figuring a man-to-man conversation could clear things up. But no, it almost ended in a fight.
These people function on emotions, there is no rationale in them. They might be rationale for 10 minutes a week or so, when their emotional pendulum has lost momentum for a little while. But they are always scheming. They have no honor. They have no integrity, no dignity, no conscience. It's all about gains for them. Sociopaths, psychopaths, whatever you want to classify them as. They can have friends, they can know how to manipulate people into giving them things, then when people cut ties, they will try to break you down to 6ft under. It's really a trauma to spend too much time with them. Problem is that they are simply fun to be around when you're getting to know them - before you find out that they have no soul, lol.
Best thing you can do is just fux with people who really have proven to you that they will give without wanting anything in return. Deal with selfless people! I bet tons of the members here have ego issues. That's where all this sociopathy and psychopathy stems from. Peoples egoes. They see themselves in a certain way, don't want to be seen in a different way. They believe their own lies, or don't care what they do to others because they equate their egoes not to virtue, but to resources. Nothing you tell them will make them feel bad. They love to be hated, I've heard some people say. The only thing that can make them feel bad is a personal loss to them, and if you inflict that on them they will do whatever they can to break you down.
And all the time you have to remain non-reactive, because any reaction will just be gas to the fire.