Most Helpful Girl
They probably date those guys because they are attractive, not because they are obnoxious.
They probably don't date you because you're not very attractive, regardless of how sincere you are.
Most Helpful Guy
Could be other factors like they are dating rich or hot guys regardless of whether they are douchebags.
It could also be that your 'obnoxious' versus cocky line is miscalibrated and you are judging plenty of direct and actually welcome behaviour as obnoxious while presenting a sanitized and actually less sincere version of yourself.