Japan wasn't a feudal society 100 years ago, in fact, they had beaten a western power 10 years prior.

Not to mention the 'West' just finished 4 years of blowing each other up, not very "Civilized" imo.

And also not to mention that while their internal justice may have been questionable (as it always is, everywhere), the Edo period had zero war for 250 years. Imagine the US never having been in a war since before the Declaration of Independence. Would that GP included that in their criticism.

Their constitution was drafted mostly by the Americans. I don't think that's a fair conclusion to draw here.

The feudal era in Japan is considered to have ended with the shogunate, ie the Meiji restoration (1868).

To be fair to the OP I don’t think they were invoking the end of the shogunate but rather that because it had ended within memory of the defeat to the allies, these vestiges were relevant and were (and continue) to be in the conscience of Japanese society.