There's a reason why "nice guy" is a stereotype. The people who describe themselves like this aren't nice or timid, but insecure, angry and judgmental. They tell stories like "women like assholes" to avoid coming to terms with the idea that they're unlikable.
And it's not that women like assholes. Rather, people (not just women) like the traits that let an asshole get away with being an asshole.
This is especially true when eveyone involved is young enough not to have a wide enough frame of reference to gauge what's an indication of actual confidence versus abuse and has a brain undergoing massive hormonal shifts that intensify emotions, encourage risk taking and make them seek out novelty. Let's remember that most of the "nice guy" stories people like to tell are about early adulthood or more often than not their late teens.