Yes, the whole "Towers of Hanoi is a bad test case" objection is a non-sequitur here. It would be a significant objection if the machines performed well, but not given the actual outcome - it is as if an alleged chess grandmaster almost always lost against opponents of unexceptional ability.

It is actually worse than that analogy: Towers of Hanoi is a bimodal puzzle, in which players who grasp the general solution do inordinately better than those who do not, and the machines here are performing like the latter.

Lest anyone thinks otherwise, this is not a case of setting up the machines to fail, any more than the chess analogy would be. The choice of Towers of Hanoi leaves it conceivable that they do would well on tough problems, but that is not very plausible and needs to be demonstrated before it can be assumed.