From a guy who experts in weaponry and fighting, I know the guy is very knowledgeable (also his videos on castles is fantastic), as I said I have no issues with his knowledge on that front, its his nit picking, over analysing, and over the top hate of the show catering to the toxic fandoms that I have an issue with.
I mean going back to his sword autopsy, its like anyone who works in a certain profession, for example my sister is a nurse, and whenever she sees nurses or medical staff on TV act a certain way she would go 'they make it look so easy' or 'that's not how that works'. Things wills stand out to you if you are in that position. I had a friend who was a cop and he'd say if TV cop shows were accurate they'd be 70% of the movie of them doing paper work lol.
It can be fun to highlight bad chorography in shows or highlight things that are not accurate, if you are knowledgeable on that subject, but to a general audience no one really cares. (well until they see the videos highlighting it and then all of sudden people now care)