Why does D&D always make all the cool looking stuff evil?

Gnolls? Evil demonspawn that can't stop eating people.

Owlbears? Violent and untameable.

Dragons? Greedy assholes that think they're better than you.

Various slimes? Will dissolve you. Can't even keep them as pets.

These silly glooby eye monsters?

Wizards of the Coast please hire me to make your game better. OK that's all.