How the Hell is the Unicorn a Symbol of Purity?

It has a huge phallic horn on its head. And the legend goes that it will approach a virgin and lay its head (with the huge phallic horn) in her lap.

What the fuck is pure and innocent about that?

And it's considered something desirable to pet these perverts in fantasy stories?

To Hell with that. I see a Unicorn, I'm running, and I'd advise you to do the same.