What made him this way: Genetic autism and an upbringing by parents who were too old to understand his needs, therefore not meeting them. Also, being raised by pop culture with no friends. The trolling certainly didn't help.
What is the attraction: People love a trainwreck, and not only is Chris a trainwreck, he's the original internet trainwreck. He's been grandfathered in, despite tons of equally degenerate weirdos being out there. The fact all of the crazy shit is heavily documented also helps since you can go on the Cwcki and browse for hours, or watch a 40+ part documentary series going over every aspect of his life. Not saying that he isn't a weirdo who's done a lot of crazy shit, he has and that's the main draw, but the fact he's done so much, it's all been catalogued into easily digestible formats, and he's been around longer than almost any other cow puts him over the top as THE lolcow.
What keeps us fascinated: Chris's early lolcow status means he's become a mainstream internet meme. He also consistently keeps getting worse.