Nice try, Paul, but no cigar. When the CP moved into its Popular Front phase, Black membership in the party began to drop steadily, especially in the South. This was due to the CP's decision to tone down its rhetoric on the struggles of the Black worker in order to broaden its appeal among "white" workers, southern liberals and progressives; to what Hosea Hudson called "institutionalized white chauvanism"; and to an impatience on the part of Black CP members with being called "Comrad N-word."
That the "left" in general has had its (relative) shining moments of "racial solidarity" (another problematic term) there is no doubt. Scottsboro is one of a number of examples that inspire hope. But there is also, however, no doubt that those shining moments have been just that. That's because the "white" left, unsurprisingly, has never been very good at perceiving, never mind understanding, its own whiteness, be it subtle or overt. Scottsboro notwithstanding, the Popular Front is just one of many examples of "white" lefties abandoning a relatively hard core stance on the question of race in order to appeal to a broader base of "white" workers, etc. Lot's of Black folk saw the writing on the wall and decided to do something different.
Niles