The other me was ready to go kill Sam. And I found another way to help him, there was a way to get the angel out of him. Vampires are different.
And as for Ellie, she's part demon, but she's sealed. She has no powers what so ever, and Castiel made sure of that. She's practically a normal child. She's too young to even know what she is.
Because I said so, that's why! Vampires, shifters, ghouls, ghosts, angry fucking spirits, I'm not letting them live. Unless Damon suddenly becomes a pretty little veggitarian vampire, and stops risking everyone's life, I ain't playing this game! Adam's my fucking brother! My family is at risk. Is Sam a danger right now!? No. Is Ellie able to act on her demon parts?! Absolutely fucking not. Is Adam risking everything because Damon's alive and able to turn anyone he fucking pleases into a vampire? Yes.
If you don't it, why are you a hunter? We don't pick and choose nice monsters from not so nice monsters. Vampires kill innocent people. Demons kill innocent people. The only half demon I've ever seen not hurt someone was the little kid named Jesse, who didn't even know what he was, and he ran away. He was young enough to help, and Castiel wanted to kill him.
So don't give me this oh don't hurt the vampire because it hasn't done anything wrong shit. Existing is wrong. Eve is fucking wrong. If you aren't going to help, I'll fucking keep this town safe by myself. Demons killed my fucking mother. Monsters killed people I cared about. That's why I'm a hunter. Not to have a fucking tea party with those I think are reasonable.
I took up this job to protect people. And if my dad knew Damon was a vampire? He'd be dead already. I've made a mistake in letting him live. It's wrong.
... Wait. Why- You-... I think I had a dream you- Never fucking mind. Unless you're going to try and stop me? I'm cleaning this town up. And I'll get my old man and mom involved. And the Harvelle's. They're all itching to know what's really going on.