For this post, I won't explain why we love to learn about the abnormal, but why we should. Looking at that youtube vid of a two-legged kitten is fun, but maybe it can mean more than that.
Secondly, one could argue that it fosters a more accepting environment by expanding our view of reality and opening our minds to diverse practices.
When I worked at the rock wall at California State University, Northridge, one of my co-workers was reading a magazine, and she expressed alarm at an article that was written there. It detailed the relationship a woman had with a younger man, a man who was friends with, and more similar in age, to the woman's daughter.
“Isn't that weird?” my co-worker asked.
“Not really,” I said. “I've seen weirder.” I didn't mention it, but I had read of a man who married a dog, and a woman who married the moon. There's always something weirder, and at some point you just accept that there are strange tastes out there. I'm always interested, but it's hard to put me off or freak me out. In other words, through my knowledge of diversity, I'm more accepting of the marginal lifestyles.
Of course, that's not to say that the strange are always portrayed fairly. Ask any person whether their profession, hobby, culture, or they themselves—strange or not—have been portrayed fairly in the media, and they will say “no.” No matter how hard a journalist tries to get the full story, someone will think it's unfair. C'est la vie.
Learning about the heterodoxical can also teach us about the normal. For example, in the book Mutants: On Genetic Variety and Human Form, the author discusses diprosopus, or the formation of two faces on one person or animal. Creatures with this condition have an excess of a protein called Sonic Hedgehog Homolog, the gene that controls for facial width. Cyclopes, who have a face so narrow that their eyes merge into one, don't have enough of this protein. Without the cyclopes and two-faced freaks (and of course I mean that in the most endearing way), we would have known of no connection between face widths and the Sonic Hedgehog Homolog protein. To a biologist studying embryonic development, there are pertinent implications.
Sometimes, though, we learn about the strange and determine that it is actually a normal thing. For example, say you do something particularly strange. Say you're not attracted to anyone, and you are asexual. Then you see an article or news segment describing a strange culture of people as bizarre, maybe “messed up,” a group of asexuals. AVEN, the Asexuality Visibility and Education Network, brings together people to discover that there is a group of people who feel the same way. Although it's likely that the group was portrayed as an oddity, and others look at the group as weird, you've just discovered that your little strangeness is not unique, and ultimately it's just an uncommon variation.
So learning about the unbelievable has a lot of implications, from scientific to social to just entertainment. Perhaps these are the reasons that we love abnormal, because it expands our minds and has real-world implications. So, here's a picture of a unicorn (tricorn?) cow. Expand your mind with it.