She could be (and probably is) a pathological liar. That doesn't mean she is incapable of being raped. It only means her accounts shouldn't be published and she's not a reliable criminal witness.
It was torn to pieces by WaPo, CJR, and the Charlottesville police. There is no doubt that it was a hoax. If she has ever been raped, it was a completely different event from the one described by the Rolling Stone.
On the other hand, I don't think that Jackie is a pathological liar. She tried to catfish a guy[1] and get a little sympathy from college admins. She started off like a fairly reasonable liar (for a teenager) and got caught up in the whole thing. She's definitely at fault but much less than the Rolling Stone which went on a rampage defaming people left and right and instigating a mob[2].
[1] https://www.washingtonpost.com/news/grade-point/wp/2016/01/0...
[2] http://www.nbc29.com/story/27439468/uva-fraternity-house-van...
Sabrina Erdeley has herself written that she went out looking for a particular story. This is among the reasons why she is liable. In the US the standard for that is much, much higher than just failing to hold up in court. It takes actual malice.