/u/mocny-chlapik thinks OP paper is suggesting that LLMs don't understand by pointing out that differences in how humans understand and how LLMs "understand". /u/mocny-chlapik is criticizing this point by showing that this is similar to saying aeroplanes don't fly (which they obviously do under standard convention) just because of the differences in the manner in which they fly and in which birds do. Since the form of the argument doesn't apply in the latter case, we should be cautious of applying this same form for the former case. That is their point. If you think it is not a satire meant to criticize OP, why do you think a comment is talking about flying in r/machinelearning in a post about LLMs and understanding?

I don’t know who was the first to use the analogy to bird flight, but it’s a somewhat common refutation used in philosophy of AI. That’s just to say, it’s been used before.