Why are so many guys on the internet "white knights"?

For those not in the know, a white knight on the Internet is a male who comes across as desperate for female attention. Trademarks of a white knight include:

- Always rushing to defend a woman at any cost, even if they are uninformed/not part of the discussion.

- Always complimenting women, even where not appropriate. For example, a woman may post a picture of herself wearing a necklace she wishes to sell and ask for advice on how much it’s worth. The white knight will invariably compliment her appearance whether he answers her question or not.

- Not being able to write more than two sentences directed at a female without including the word “sweetie” or “hun”.

- Always responding to any topic/inquiry by a female even if they have nothing useful to add. Examples of this can be seen in forums where when a male will create a topic it will get a handful of replies, while a topic created by a known female users will get a few dozen.

Why do guys online do this? is the stereotype really true that they are all virgins/never touched a titty?