It's no big secret that women are often bombarded by messages and other overtures on dating sites. Perhaps the "viewing males as more unattractive than they might otherwise" just stems from being primed for pickiness, especially on the Internet.

If you meet someone at a party, maybe he's a friend of a friend, you talk to him for a while, you might think "He seems like a reasonably handsome guy!" You see the same guy as a profile picture, out of a sea of 20 others messaging you at the same time, and you're just mentally primed for reasons to reject people, rather than accept them. You're more likely to think "Ugh, stupid haircut. 1/5 stars. Would not date"

So I don't think that women have unrealistic expectations of beauty, in general everyday life, it's just that the motivations and mindset is so much different on dating sites.

The data doesn't show that. It shows behavior on okcupid sites. Presumably. I don't understand why we blindly believe this data given many known issues about psych and sociology studies.

They are critical, but not unrealistic. From that blog:

"As you can see from the gray line, women rate an incredible 80% of guys as worse-looking than medium. Very harsh. On the other hand, when it comes to actual messaging, women shift their expectations only just slightly ahead of the curve, which is a healthier pattern than guys’ pursuing the all-but-unattainable."

You can also interpret that as "women would rather date guys they think are ugly than be alone" (as the author does in the following sentences).

Isn't that being realistic though?

Only if you assume the default position is needing to constantly have a partner