http://www.livescience.com/13356-el-chupacabra-mystery-solved.htmlSo are you asking for our opinion of unicorns or for validation of your claim?
I'll give both. No I don't believe in unicorns, any more than dragons, fairies, griffins or chupacabras.
And my opinion of "just because you haven't seen something, doesn't mean it doesn't exist" is that it's selectively applied. If you aggressively believe in unicorns, do you equally and aggressively believe in fire-breathing dragons, child-killing fairies, man-eating griffins, and blood-sucking chupacabras? These are all fantastic creatures embedded in mythology, and haven't been seen, only stories told and pictures drawn.
I agree. I think that people cling more to unicorns because, as you said, they are positive. Like most religions and myths people want to believe in something that will make them happy and give them hope and help them to see beauty and love and magic and maybe even a bit of retribution in a world where there doesn't seem to be any; people like to dream happy dreams and have sweet magical fantasies, it's a sickness. But I think the unicorn is solely a myth. Aside from the link I attatched above I don't think anyone ever sees horned and winged horses prancing around in the woods, but we constantly hear of alien sightings or people who've had livestock eaten by chupacabras or big foot-sized footprints, or hear of people who saw the Jersey devil. Maybe it's just a case of mass hysteria or maybe, as I said, some myths are based on facts.The reason why I listed those other creatures alongside the unicorn is that the vast majority of media surrounding unicorns is gentle, beneficial, magical, and positive. Unicorns are bright and pure symbols of pride and strength. When unicorns are hunted, it's an unforgivable crime, at worst a sin.
But you will get stories of monsters that eat people alive, fairies that steal children sleeping from their beds and chupacabras that suck herds dry. They're horrible and often frightening. But these creatures have everything in common with unicorns in that they spring from mythology and folklore, have never been seen conclusively, and are regularly depicted in art and literature. Rarely do you get a story of someone gored to death by a unicorn's horn or trampled by one.
So I ask where the difference lies in believing in unicorns against all these other nightmarish creatures. I think it selective because unicorns are "safe" and benign, whereas to believe in child-killing fairies and man-eating rocs would be judged in a harsher light.