No, Teriz, you're not evil. Annoying and super persistent sometimes, but I don't think you're generally a bad person.
Black Dragons are cool and are probably one of the most interesting of the Dragonflights lore and character-wise. Liking darker elements and characters doesn't make you evil. What you say and how you behave towards others determines how you are perceived.
The black dragons were once noble protectors of Azeroth and of the races who inhabit her, led by Neltharion the Earthwarder at the height of glory and prosperity. Then came the fall and it was mighty one at that. Neltharion was corrupted and maddened, the rest of his flight followed him to their destruction. Then, when all seemed lost, Wrathion came to be thanks to Rheastrasza's meddling in Cataclysm. He's trying to bring his flight back from the precipice of extinction, to redeem them and recover their lost legacy as protectors of Azeroth. It also helps most black dragons looking fucking cool.I tend to like characters/races who had a fall, fight their dark natures and wish to reform.