Well that can be a mixed blessing, yes it's a good art style but with it comes a peculiar form of US racism left over from WWII. It seems to be impossible to have an Asian person who Isn't a ninja, and some of the shows are nothing short of crap (Example: Shaolin Showdown, Shuriken Acadamy and Justice League.) And when Anime is imported to US TV the voice actors are horrible, and there's just too much bad rap.
Personally, I think it falls more into stereotypical entertainment category of any culture. Racism is a strong word that is well-abused now days. I don't think any American cartoons deliberately try to enforce the belief that all Asian people are ninjas. I think they're just credited as being good at the role. Just like blacks are usually credited as good basketball players.
That's just my observation though. I've seen far too many people cry "RACISM!", when it's actually just companies trying to make money off popular concepts.