...is this a thing? Are there actually people who think France - the terror of Western Europe for centuries, the bad boy nobody wanted to cross, the power that once marched all over everything between the Meuse and the Vistula and only got stopped because basically everyone who wasn't France united to fight back - is somehow militarily incapable?
That's even dumber than the cheese-eating surrender monkeys meme.
Yes, strange as it may sound, opinions to this effect had been more than once expressed in SHM group even by the professional medievalists. It seems that many Anglophonic authors tend to present rather biased versions of the 100YW as consisting of 3 famous battles (with nothing worth mentioning in between except for the English victories) after which by the reasons unknown the English side lost all its possessions except Calais. Needless to say that Agincourt was presented strictly along the Shakespearean lines. It was always French stupidity and arrogance and their vastly superior numbers against "we few....". You can find a nice illustration in Keagan's "Face of the battle". Pointing to the non-British authors like Delbruck who presented a seriously different but logical picture was a waste of effort because "everybody" knew that the French were stupid, etc.
By extension, the same goes for even more popular "the French are lousy soldiers" with the only exceptions being two semi-foreigners (Joan of Arc and Nappy). Does this notion need any comments?