There exists an argument that people who are not white are, in fact, capable of saying or doing things which tend to discriminate against white people; and furthermore that such speech and action is harmful and morally offensive.

"reverse racism" is a term used by people who find that position disagreeable or inconvenient, to mislabel, misrepresent and mock it.

The argument is not at all "far right"; it's centrist, and obvious. But certain extremist identity-based ideologues have manage to sell that nonsense with their propaganda based on the label. Occasionally you will see people who don't know any better use the term unironically, because of the dominance its derogatory use has achieved; but serious opposition to so-called "progressive" identity politics does not actually use the term.