"It sounds like sci-fi" isn't a valid reason to think something is impossible. Many things in the modern world would have sounded like sci-fi 50 or 100 years ago. This type of reasoning has a name: https://en.m.wikipedia.org/wiki/Appeal_to_the_stone
I don't think human or greater artificial intelligence is impossible. I do think the specifics of how it works are both very important to any ethical problems and not currently predictable. My objection isn't that alignment problems sound like sci-fi but that they're very soft sci-fi, and aren't based on meaningful predictions.
