Bruh there is literally a popular media character called Captain America.
If you were trying to satirically come up with the main character of a state propaganda show, a name like that would probably come to mind. For satire.
Imagine how US Libs would react if a superhero called Captain China started getting really popular.
Not to mention the fact that captain america isn’t censored or anything in China.
If you changed up the colors on his shield just a little, he could easily be Captain DPRK.