Yes it's because Danny isn't Asian. This is also linked to the Ancient One mess for Doctor Strange. Now, writers have created great Iron Fist stories, and the Cage/Fist friendship is legendary. But honestly, Iron Fist is a throwback to the "white guy who learns a skill from another culture and outdoes the people in that culture" trope. It's problematic.
Marvel has made great strides in representation of black people in their comics and the MCU (movie and TV). Captain America is now black. Spider-Man is now black. The Black Panther movie is going to be The Event in 2018. And the Luke Cage show on Netflix was a best seller. And in order to do all this, Marvel had to retool and look at their black characters and their portrayal of black characters in a modern way and bring things up to date.
So. Some Asian Americans see all this and want the same thing. They have the new Hulk! They have Ms. Marvel! Things are looking good, and then...The Ancient One. They are still probably side eyeing Marvel for the Mandarin, but that was nothing next to this. I guess they thought that Marvel would find a way to pull off "respectful but representative", like they managed to do with Benedict Wong as...Wong. But Marvel punted to Tilda Swinton. Asian American actors are hurting for work, now one part they
could get is taken by a white woman who is always working.
And here comes Danny Rand, the David Carradine of comic book characters. A white man stealing their cultural lunch. So, if Samuel L. Jackson can play Nick Fury and Idris Elba can play Heimdall, then Danny Rand can be Asian, right? Make him a kid who is distant from his culture and earning the Iron Fist is his journey back to his roots. How much is Rand being white shaping the character? Is it the rich kid part that makes him have to be white (and man, Arrow TV show fans must be confused right now), much like how Bruce Wayne being an old money rich white kid shapes his character?
TL
R Some Asian American comic fans want Danny Rand to be Asian, and I'm cool with that.