It's a right wing talking point about how some people in the US are being held to account for their actions for more or less the first time, particularly in regard to racism and sexual violence. Cancel culture to the right is wanting to remove someone's status or influence based on past actions. To us, it's just doing the right thing and making people responsible for the distasteful things they've done.
Mine is that International Workers Day is May 1st to commemorate the Haymarket Affair, which happened in America where labor day is conspicuously much later in the year.