But of course if you define the situation simply as "Fe thinks something is x and then says it's y," it's inauthentic pretty much by definition. But that misses the true whole paradigm that Fe is drawing on. What Fe already thinks is more like what you come to at the end of your posting: Fe-person might think it's ugly in the aesthetic estimation of the particular Fe-person BUT realizes that the entirety of the universe is not subsumed in the particular Fe-person, and so, noting that otherperson is of a different opinion, grants that there is a reasonable possibility that otherperson's opinion could be correct as far as otherperson's aesthetic goes, which overall has just as much right and validity as Fe-person's has. And so, rather than to in effect say, "I'm me, and everything I say or think is the final word," Fe-person, seeing the bigger picture, allows for otherly beauty. What's the point of insisting that it's ugly when it's already an established fact that no single person has a monopoly on such aesthetic decisions? Rather, it's being parochial and childish. Fe senses the larger world, respects it, and renders opinions and observations which are unselfish and authentic in representing Fe-person's view of the world. The question asked of the Fe-person was, "What do you think?" Fe-person thinks that all things can have beauty, and that, in considering things, it is desirable that self-absorption give way to selflessness, that narrow views give way to wider views. The way to truth doesn't come from little pointless squabbles between individuals but rather from personal and private epiphanies. Fe-person does not see that authenticity is bound up with selfishness; Fe-person's notions of authenticity are on another plane.
And if you ask me, "Well, then why didn't you just agree with me?", I'd answer, "Because we're here to engage in pointless squabbles."