Yes, it’s a generalisation (for which I apologise), but I am just curious as to what the psychology behind this precept is.

I can only assume it’s because bastards display a high level of strength, albeit through being bastardly.

Some women get hung up on the idea that they can make a man change his ways through the power of love. This can be seen quite a bit in stories, though the only thing that instantly springs to mind is “Guys and Dolls” and its ilk - the gangster’s love for the innocent and religious girl makes him change his ways to please her.

In reality this probably doesn’t work as much. Whether some women think this will work due its success in fiction, or if fiction is simply reflecting the hopes of fantasies of said women, I’m not sure.

I don’t understand why some women want to change a man. Why waste time when they can just look for someone who’s already ideal?

Some women love the feeling of excitement from going out with a guy who’s a bit “dangerous”. Being a bit of a bastard may also mean that he’s on some level a mysterious guy (because he’s being perceived to not be showing his true and vulnerable feelings?), and some women really like a guy who they can spend some more time figuring out instead of a transparent one who they can read easily. If he’s not showing blatant interest in them, it makes him more intriguing and more of a challenge.

A mean guy can also seem like a strong/tough guy, which might evoke a desire to be on his side rather than in opposition to him, so they can be under his protection.
I personally value myself and so would not put up with, let alone be attracted to anyone who treated me like crap. Some women though subconsciously seem to seek out men who reinforce their low self esteem by verbally and sometimes physically abusing them. As twisted as it is, sometimes this is even more likely to happen if they had an abusive father, as they witness his behaviour as their first example of what a man should behave like.

Most ladies I know would tell a guy he’s a bastard if he was one (and sometimes even if he wasn’t).