Plenty of guys (particularly on this website) claim to be nice guys and that being nice is why they are unsuccessful in dating. They also notice that players are successful with girls and often don't treat them well.
Correlation Isn't Causation.
"Players" Are attractive to girls, either physically or in some other way - if they weren't they wouldn't have any luck with girls. Being attractive enables a guy to be a player, and he doesn't need to be nice or good to do that. It's not that girls particularly want a selfish bastard, it's just that attractive guys attract girls despite that, because they are appealing for other reasons. There's more to a person than being nice...
Basically being attractive is necessary for a guy to a player or a successful bad boy type (that get's with lots of girls), and being so attractive they don't need to worry about pleasing the girls they pursue, or being nice or kind - except perhaps on meeting or occasions when it may be needed to score.
Less attractive men can't get away with being pricks if they expect to have any luck with girls. You may be nice, that isn't why girls don't like you. If you decide to act like asshole that won't make you more attractive, it will just make you unpleasant.
So my advice to guys who think they're unsuccessful because they're "too nice", try thinking about whether there might be another reason girls don't fancy you. You might be able to do something about it. Becoming a misogynist won't help.