It's not fearmongering to state objective facts. Lower classes as a whole do worse under Rep leadership, and unfortunately black people still disproportionately make up those lower classes. Maybe you're right that taking that hit is necessary to make progress, but anyone pushing a strategy has to be honest about the drawbacks and benefits of the strategy.
The Dems are terrible, but they are not equally harmful as Reps. That's demonstrably false. If you have to lie to push your strategy, you don't have much faith in it. Again, I'm not against walking away from the Dems. I just haven't seen a good argument for how it would actually benefit Black people. I'm guessing that the idea is that the Dems will take a fall and then come running back to Black people so they can win again. I'm not 100% sure that would even happen. There are other demographics in this country the Dems could court that might be easier to win over.
Either way, just telling black people not to vote for Dems is dumb. Black people need to be more organized and thoughtful than that. If we're going to refrain from voting for the Dems, it should come as part of an ultimatum with us walking away after they've failed to live up to our demands. We can't even get on board together to make actual consistent demands, and that's a problem.