What does "white knight" mean in this context?
The term "white knight" has been well documented in places such as Wikipedia or various online dictionaries. But none of those definitions seem to encapsulate the meaning from this quote:
[White knights] are renowned for beating around the bush and not saying what they actually think instead they cover their real thoughts with stupid compliments. [White knights] also notice things that your typical man would not (see below)
Typical white knightish sentence to a girl: You look fantastic did you get your hair done?
Typical non white knightish sentence to a girl: I'm hungry/horny
The above portion has a handful of various grammatical oddities but their use of White Knight does not fit the definition from the dictionary:
white knight —
a hero who comes to the rescue.
a beleaguered champion who fights for a cause.
a company that comes to the rescue of another, as to prevent a takeover.
What does noticing new hairdos have to do with rescuing people?
It's only a short step from "a hero coming to the rescue" to the top definition in the Urban Dictionary:
A person (usually a male) who sees the typical maiden in distress, and believes that he can help her. A male version of the "mother figure" that some girls become.
"Why is he going out with her? She's broken, and a little crazy."
"The fool's just being a White Knight."
Your quote merits its own mention, because that use of white knight is further twist of meaning:
According to the MISC on the BodyBuilding website: A white knight is defined as a male that treats woman as goddesses and does nothing but shower then in compliments on how wonderful and beautiful and special they are. Maybe be used as a noun or a verb.
Presumably it hasn't reached a wide enough usage yet for this meaning to be included in more mainstream dictionaries.
I'd assume that this has to do with the cynical and sarcastic usage of 'white knight'. Supposedly, an 'internet white knight' believes that by defending girls from the sexist atmosphere of most forums, the girls will like them and want to date/sex/etc them. It's a twisted modern retelling of the classic "knight saves maiden from dragon; gets maiden" story.
This could be extended to imply that this person is only complimenting the girl's hair in order to get in her pants. That person is being compared to one who boorishily (but honestly) explains his own interests and lets the girl choose whether she cares.