WHY?!

I get that a person can hate another person because the other person is a jerk. There are PLENTY of jerks in real life that people avoid and honestly, that's fine!

BUT WHY DO PEOPLE AUTOMATICALLY HATE SLYTHERINS?!

Harry Potter is (don't hate on me for this) biased. I could somewhat see why he thinks Slytherins are bad because of Draco being his rivals all those years and Voldemort. But to hate an ENTIRE house is a bit much.

Like, does nobody remember Regulus! Yeah he was a Death Eater, but he turned his back on Voldemort and tried to destroy a Horcux! And what about Slughorn?! Yeah he plays favorite, but his not a BAD guy! He has flaws and weaknesses, but who doesn't?!