While I get what that first video is saying and the Twitter users going full white savior to explain to the poor oppressed Japanese residents of Japan that anime obviously looks the way it does is because they all secretly look white is hilariously patronizing, I don’t necessarily think the confusion is completely out of nowhere. I think a lot of what throws some viewers is because Japanese and American animation have somewhat different priorities when it comes to their approach in character design - particularly in terms of garish hair colors of anime - and while the video does mention that a handful of shows will give some variation to distinguish between white and an Asian character, that’s not always guaranteed often enough to be reliable, so it often depends on context. One of the characters used as an example, Asuka, is canonically 3/4s German despite not being drawn differently from the other characters.
Also Japanese fans being better cosplayers has less to do with the ethnicity if the characters and more to do with how Japanese cosplayers are more likely to be willing to spend hundreds, if not thousands of dollars to get the costumes, wigs, and photoshoots perfect.