Eh, I don't know. I don't think it's targeted at Astarion, I just think they made Lae'zel's character ever so slightly worse by making that possible. So rather, I'd prefer if they removed the Lae'zel and Mindflayer romance rather than making Astarion also be A-OK with it.
I also felt that the Elfsong Tavern scene felt a lot better than what I imagine is the alternative by virtue of him coming to terms with the fact he can't be with you. A version where instead he's okay with it would probably be more boring, I think. It's different with say, Gale, where you can see how enthusiastic he is about the whole ordeal still: It adds to his character, rather than detracting.
There's also a bit of a spectrum here when it comes to accepting Tav, since IIRC Wyll also accepts a romance with Mindflayer Tav but it's kind of... disturbing? He keeps you in some basement or something. I'm not sure if they changed it, or if they even intended it as creepy because that's not a character I'd expect something like that from.
