It's the unspoken part that drives the difference.
Sure, but a lot of people will deny the unspoken part even if you ask it explicitly. They aren't just being polite by not saying it, there really is an effort to enforce a fiction.
Ever seen that podcast "whatever"? I don't recommend watching a
lot of it, but watching
some of it can be quite educational. They usually have young women on as guests (usually several at a time), not usually celebrities, and ask them all sorts of stuff about relationships, dating, etc. The reason I don't recommend watching a lot is that most of them are stupid, and don't have anything intelligent to say. (Note: these women are not a representative sample of women in general, but they ARE a sample of a type that exists out there. And I'm sure you could do something similar with stupid young men, so don't misinterpret this as an attack on women). But seeing the sorts of justifications they come up with for their opinions and behavior is illuminating. The host will often ask the guests to rate themselves on a scale of 1 to 10 in terms of physical attractiveness. And so often, they'll rate themselves a 10 when there's just no way that any honest assessment could possibly put them that high. Now SOME of that may be self-delusion, but I don't think all of it is. I think a large part of it is trying to enforce a fiction of solidarity. In one case I remember, a bunch of them rated themselves as 10s, and one of them rated herself as a 7, and she was one of the more attractive ones in the group. And the other girls got pissed at her for saying that. In terms of how I would respond in similar circumstances this is odd, because I'm more likely to react negatively to someone boasting than to someone being humble, which suggests a very different group dynamic than I'm used to. It was like her modesty threatened their fiction, and they turned on her to try to coerce her to play along with their fiction.
Saying trans women aren't women threatens a fiction of solidarity as well.
So when you tell someone they look like Lizzo... they will 100% assume you mean that they're fat.
What's more, they will assume (probably correctly) that you aren't going to play along with their fiction.