AIUI, Heinlein did soften the racism from Campbell's original idea (adding Frank Mitsui as a character, e.g.), but it was still awful. Note that Mitsui is rewarded for his existence as a token by having his entire family killed horribly in backstory, and then dying nobly to stop the nutbar white guy.

Now that I think on it, the nutbar white guy starts out espousing a few positions not far from Campbell's, in some ways. I wonder if Heinlein did that on purpose?