Except "Reverse Racism" has a specific meaning, which is racism against a majority group (e.g. white people). There are people who believe that you can't be racist against a majority group, that it's called "reverse racism", and isn't a legitimate issue.

Racism is racism, whether the group being stereotyped is a minority or a majority. It minimizes the detrimental effect of a racist behavior to say it's "reverse racism". It's euphemistic language that serves no purpose in its colloquial usage other than for a member of a majority group to claim victimization, usually when they themselves have exhibited a prejudice against the "reverse racist".

EDIT: to be clear, people who believe that reverse racism isn't a thing are semantically correct, it's just racism. And whether it's against a minority or majority group - terms which, themselves, are prime to define a disparity between two groups - it's unjustifiable.

What you just described is still called racism, no need to prepend the word 'reverse'. But, I doubt many people are going to take fears/claims of discrimination against white people in western countries seriously, because it's either a cover for actual racism or paranoia.

Presumably, since up further in the CoC you're expected to be welcoming to people of all races/sexes, you can't treat white people like crap. This technically wouldn't be "reverse racism", but should still be prohibited. I have very low expectation that this framing would be recognized though, based on how these things have played out before.

It is also not clear to me if the CoC applies to behavior outside the community, or re. nonmembers.

There's no such thing as a majority group. "Minority group" is a sociological term, not a mathematical one.

"You cannot do / say X because you're skin color / gender / sexual orientation Y" is racism / sexism, end of. "Affirmative Action" (which is doublespeak for "we prefer minorities") is racist/sexist too (and often referred to as being reverse racism).

If it's "not a thing", why do they need to list it? Wouldn't their existing prohibition of racism be sufficient?

Reverse racism is used (in my experience) to define racist behaviors taken as a response to "original" racism. Examples include quota systems at universities, or otherwise discriminating against whites/majorities in the name of social justice.

It's racism, but with a modifier to make it clear what's being talked about. I don't know why you're trying so hard to make it "not a thing".

I would guess it means the same as positive discrimination? At least, it would make sense if they did nothing against that.

Racism according to its academic description has to be systematic. i.e. A white person can be discriminated against because they are white but because its not systematic, i.e. within our social system infectiosly, its not racism.