@Eiuol
I think Intrinsicist is saying that while you can make inferences about new winged things, you are not justified in doing so, because there is no universal "out there" which could serve as the subject of your universal judgments about winged things.
That is, according to Intrinsicist, since you don't believe in real universals, you would have to concede that there is no fact of the matter in a statement such as "all winged things fly", even though there is a fact of the matter in ALL statements such as "this winged thing flies", "that winged thing flies" (where 'this' and 'that' refer to specific given winged things).