Denying essential humanity to anyone is always and everywhere unacceptable. "Unattractive men are animals, not human beings" isn't provocative, it's totally beyond the pale.
If the essay called an ethnic or religious group animals, would you still link to it and characterize it as "interesting" and "provocative?"
In the context of the article, "animal" is meant to be understood as "something having non-human features". An ugly guy has both human and "non-human" features, so a mind is split in those both directions, and the split evokes the feeling of creepiness.
Just because you feel bad about something it doesn't mean it's false.
Well if saying anything you like as long as it is meant to provoke [a response] is acceptable, then let's have a few articles about why antisemitism is cool and how black people have low IQs. Or are those subjects that have been covered and people have been both prosecuted over and been fired from their jobs for?
Being provocative at least requires starting with an argument that can be defended.
If the essay called an ethnic or religious group animals, would you still link to it and characterize it as "interesting" and "provocative?"