I read the article and don’t see how it quite says that. I can see how that’s inferred since Biden’s opponents are mostly communists, but the article seems to suggest that they don’t really prefer anybody after him.
You must have missed this: “As for the general election, a lack of intensity among younger black voters could easily cost the Democratic nominee the election. The younger generation has proved itself to be more independent, more liberal, and not as content to accept the status quo as their elders.”