Everyone is racist to some degree or another - that is if you go by the textbook definition. the only difference is the manner in which different people express this preference. For example, if you're a white woman, and you would never consider marrying an Asian man, you're racist. Black men who don't find East Indian women attractive are racist. Hell, our discriminatory nature goes a lot further. If you don't find overweight women attractive, you're discriminating against fat people. Only like blondes or tall women? You discriminate against short people! If you're white and you don't hang out with black people, guess what? Same in reverse. All nationalities, all races, prefer their own to people not their own - even if they don't vocalize it and it's subconscious. People need to understand that this "flaw" if you want to call it such, is simply human nature, although we see examples of it in the animal kingdom as well.
Being vocal - and insulting - about races and your preference isn't the best way to go about a discussion on the topic, but some people choose that way to express themselves. If words have such power over you, then you really need to look introspectively to see how to fix that, because you'll never run out of people who offend you with words. The only way to stop it is to pass through it.
There are a lot of posts on the P+R forum that I find offensive, but I'm not going to get into it with people because it's their opinion. How can you argue with someone on their opinion? Maybe you'd be the same way had you walked a thousand miles in their shoes. Maybe you wouldn't. The only arguments/discussions to get in are situational, or solution based. Ie, you can argue over the best way to bring welfare to the poor, or whether there should be welfare in the first place. But if someone says "I feel that poor people bring it on themselves"...how can you really argue with the way they feel? The best you can hope for is to ask why and try to change their mind (good luck). But feelings, which is where these offensive discriminatory remarks come from, can't really be debated.
Point is, you need to get over it. For your own good.