I usually ignore these, but time for my take: No one has ever made fun of someone for being a nice person. However the buzzword "niceguy" is different. They are making fun of people too weak to be emotionally honest with those around them.
People are capable of being nice in general and still knowing what they want and being assured enough to take it.
I was raised by a single mom and I am not respectful and polite to women to try to get into their pants, it is just courtesy. If I was courting someone I would be direct and honest, because hey that usually works.
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http://firsthour.net/screenshots/suikoden-2/suikoden-2-luca-blight.JPG
The Cult of Personality.