The issue being discussed isn’t stereotypes, although that is another important consideration. You actually, in your dismissive way, bring up a very valid point.

...if you don’t think comic books can be racist, I can’t help you.

Also, Bricken was saying that this isn’t a case of “damned if you, damned if you don’t.” Read the actual article.

“So white people can’t be good at martial arts, only Asian people?”

Then change the narrative. Make him Hispanic or half-Asian or something. Anything other than a white dude.

MicroAGGRESSION

That trope is completely racist when the outsider is white.

You also completely missed the point of the article. The point isn’t the white people can’t be good at martial arts, it’s that the story trope of “White Dude goes to foreign land and becomes better at martial arts than any of the natives” is a racist trope that could have been rectified.