‘ALL WHITE PEOPLE ARE RACIST’ is the mantra of third wave feminism.
It's based on inter-sectional reasoning that says each individual group is oppressed by another, with white males being the only ones who aren't discriminated against.
Most other clear-thinking people would reason that singling out white males is in itself discriminatory, but people like this refuse to hear such an argument.
There are lots of videos on youtube with people being accused of being a "white male" just to shut down any valid arguments that they might have. It even happens on TV discussion programs.