Yeah cause we talk about shit that is real. https://www.mentalfloss.com/article/12690/why-are-people-who-cross-picket-lines-called-scabs

From blemish … to strikebreaker, the history of the word scab … shows a displacement of meaning from the visceral or physical to the moral register … Just as a scab is a physical lesion, the strikebreaking scab disfigures the social body of labor—both the solidarity of workers and the dignity of work.

Its from Norse and entered the english language in like the 1300s. I mean if you wanted a bit smarter of a grift you would go with "blaggard" pronounced "blackleg" which was used back in the day for scabs and class traitors. it has nothing to do with race, and probably comes from cheating while playing cards, but it would be easier to lie about than scab

Also you can tell how little someone cares about the racism in unions in america around the turn of the century given that they conceive of it only in terms of modern racism. You would bring up the very much literally enshrined exclusion of Chinese workers as well. That and ya know.....the bosses intentionally brought black people and Chinese laborers in after depriving them of jobs in order to strikebreak. But nope must just be cause racism just happens