We have the motives of a few who have let it slip out. One who admitted to being a paid and on a salary Obot troll. Another who married a foreign wife and so wants his child to be a natural born citizen.
A couple of them admitted they get their jollies by harassing the threads. And several were no doubt paid operatives who are now dead and gone - Michael Michael/Ender, the guy who claimed he forged the BC, gosh - tons have gotten banned actually. Some DU trolls.