The supposed distinction between fact and opinion is pernicious. I think that those who take this distinction seriously are really thinking of a distinction between matters of taste, as opposed to things that are not merely matters of taste.

I don't think we'd usually confuse a statement about a matter of taste for one of a different sort. For example, when I say "Sushi is yummy", it's completely clear that I'm making a statement about a matter of taste; someone else responding "Sushi is yucky" is not expected to provide a refutation of my claim, as they're claims about different facts.

If there's a distinction to be drawn between facts and opinions, it's that facts are the referents of opinions. My opinion, "The world is round" (if it is true) refers to the fact that the world is round. My opinion, "Sushi is yummy" (if it is true) refers to the fact that sushi is yummy (to me, since this is clearly a matter of taste).

Stating things that are opinions as though they are from some neutral perspective does not make them any less opinions, and all propositional beliefs are opinions.