I learned a lot of the English language watching cartoons. You even can get a basic understanding of culture through them.

However the crusty nerd Japanese simp is someone using pop culture to try and become Japanese. It's as silly as coming to America and dress as John Wayne and expect Texans to accept you a one of their own.

It's not about language at all it's about culture and a feeling of belonging. There's nothing wrong with it in essence. Say a Japanese dude dressing as cowboy going to a bar will probably have a good time and get entertained by texan people loving their weird fascination.

However, should they go live there and expect to be considered a true texan, they will find out that it doesn't really work that way...