I've never really understood the complaints about getting rivalry points for turning down Anders' advances. I understand the gripe that you had to be a dick in order to do so, but not the the fact that you get rivalry points. Turning people down hurts their feelings whether it's harsh or as diplomatic as possible. It still knocks people's self esteem. Nobody likes being knocked back.
Because DA2, unlike DAO, actually avoids this. DAO's Rivalry/Friendship points are about character actions. Do you do something that's to a certain character's advantage (pro mage, anti mage, etc?)? Yes? You get points.
There's also the way it was written (one "no" option to two "yes" options), and voice acted - if you refused him, it's both written and voice acted like your Hawke sees him as the most disgusting thing on earth. I'm not one of those people who believe Bioware has a secret agenda, but really.
The penalty is also equivalent to some of the most morally reprehensible actions in the game. Which, taken with the fact that DA2 generally does not do this, looks that much worse.