Phrases and insults only becone RACIST when we label them, so. If you had grown up in NYC in 1955, all of the neighborhoods were segregated, and each ethnicity referred to other ethnicities via racial slurs - it was commonplace, and it wasn't intended to be malicious. It was just a label. Today everyone is demanding a Utopia be established, and it's just not going to happen. It can't exist because there's no such thing. Even outside of the human condition, Nature segregates different groups within the same species into families, pods, etc.
So, if your feelings get hurt by something that a poster types, then IGNORE IT, and move along. Be the better person and feel sorry for them that their lives are that empty that they are compelled to hurl such insults. Let it go. Your heart will thank you, your blood pressure will thank you, and your friends and family will hail you a "Hero" for taking the high road and letting it roll off like water on wax paper.
You're talking about a "debate" forum. The word, "debate," invites contrary views, argument, and internet trolling. There is a known rule of the internet and it goes like, "LOL internet." The idea is to use internet unpleasnatries as an opportunity to learn how to ignore with grace and dignity. People are going to do what people do, regardless of whether it's right or wrong.
If you want your own forum with your own administrative powers to block users and create forum rules, maybe Webmaster will create one for you. That's the only way to insure that you will have control over what is and is not posted.
This is an enormous site and the Webmaster cannot patrol and control each and every forum board. Would you prefer Webmaster to use an algorithm that kicks users or censors people's posts? I don't think that you would. I know I wouldn't.
Take the high road.