Well, surely you're each talking about your own experiences, which are going to differ from community to community. Not to mention from person to person -- one individual might never see an instance of racism occur in front of them in a particular group, another might experience it several times, and both things would be true, since people don't always reveal their prejudices to everyone around them in the same way. Is the poly community as a whole (not that there is such a thing, necessarily) more prejudiced than any other group? I would hope not. But we do live in a prejudiced society, and poly people are just people within that society.
Note also that having a preference for redheads, but still being perfectly willing to date blonds, is very different, in several key ways, from not being willing to date or swing outside your race. Personally, I would lose a lot of respect for anyone who refused to consider getting involved with someone... as a friend, a lover, or a partner... based solely on the color of their skin -- that goes way beyond preference and is, in fact, the definition of prejudice. If one's "preferences" run that deep, one really ought to examine and unpack them (I'm not trying to imply at all, Helo, that you were saying you felt that way, just musing).
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.