Why and how do you know they are a racist?

Cause he decided to let the world know

Again, why are you stalking these people - just ignore it?

Furthermore, by codifying and enforcing whatever your personal viewpoints are in a code of conduct, you've summarily decided for everyone else as well.

Reading what someone has written under their own name for everyone to read is not stalking.

Also not sure what code of conduct you have in mind, but most specify that you should treat others with respect regardless of <list of protected characteristics>. That's not a viewpoint, that's a necessary condition for collaboration. If you feel an uncontrollable hate towards people of some nationalities or gender identities, it would be wise too keep it a private matter indeed, and not make this hate known to everyone

The point that you seem to be missing is that these are projects open to the public: if the person isn't espousing these ideas in the space in question, you're just as intolerant as they are to try and use the color of authority (a code of conduct, etc.) to bar them from those spaces.

"Treat with respect" is a dog whistle - easily coopted for whatever nefarious reason.

"If you do not agree with me, you will not participate in any space where I can drum up enough sympathy (headache) to have you excluded from."