...Conclusion: Anyone who hasn't travelled to the south pole, met the leprechaun and seen the most beautiful thing in the world can have no insight or knowledge into beauty and cannot make any evidence-based judgements or hold any rational opinions on the subject. I will hereafter refer to this conclusion as "You have to go to the south pole and meet the leprechaun" (YHTGTTSPAMTL for short)
I'm quite a fan of YHTGTTSPAMTL, almost as much as the Invisible Pink Unicorn which made a big appearance on the religion listservs a while back.
But extend your example. So agreed, YHTGTTSPAMTL is stupid, but some pigheaded martial arts heavyweight (you know who you are) is stubborn enough to actually go to the south pole, and he comes back and says, oh my god, there actually is a leprechaun and YHTGTTSPAMTL!
And some people who know him go and come back shaking their heads saying, YHTGTTSPAMTL.
And some very high-up guys say, "This is ridiculous. We'll put an end to it." And they come back and don't say anything until the third or fourth beer, at which they can be heard to mumble, "yhtgttspamtl."
The fallacy of calling it a circular argument is that you are assuming you're operating in the closed universe of logical reasoning. You're not. You're operating in the open universe of empirical experience. In that world, there's only a limited amount of denying experience which is consistent with sanity.