I’m just postulating here:

I think OP would have received considerably less downvotes if they phrased the question around the logic that led to it, or if they didn’t mention their premise at all, just left the text body empty.

Like, OP is not coming from an exceptionally weird place with the question. We’ve seen a lot of questions coming from premises just as “stupid” as this one. So what’s different and why do I think it would have changed things?

Well, this thread isn’t simply asking if “Do Evil Actors usually become Evil People?” like the title implies. Something you can just say No to and then explain the premise behind why that wouldn’t make sense. Nah, with the body text, this thread is now closer to asking “Since acting malevolent makes you more malevolent, how do actors handle evil roles without falling prey to it?”. And people are taking issue with the first half of that, because now, OP’s questions sounds like it is arguing with the answer they had in mind. I think that’s where the emotional response comes to play and causes all the downvotes.

And perhaps OP didn’t meant to cause that at all.

I agree, we shouldn’t downvote OP. This is not very becoming of the community. But it is, at least if I’m right, a weird psychological glitch.