I'm all for running the furthest left candidate with the chance to win. It's just not a good strategy when that causes the furthest right candidate to actually win. In safe blue districts, absolutely do that. In purple districts, blue is better than red, and an actual leftist is just going to spoil the vote.
You are in duty bound to call their bourgeois-democratic and parliamentary prejudices what they are—prejudices. But at the same time you must soberly follow the actual state of the class-consciousness and preparedness of the entire class (not only of its communist vanguard), and of all the working people (not only of their advanced elements).
Modern Americans are even less class-conscious and prepared than the Germans Lenin was referring to. We must soberly recognize that fact, and suit our strategies to this particularly stunted working class.
As far as I can tell, that currently means promoting leftists in the tiny enclaves where they stand a chance, nudging the Dems left in the primaries where they don't, and voting for the lesser evil when that's the best the consciousness of the proletariat allows.
Mamdani was the most leftist candidate we could get in a deep blue district. In less blue districts, we will certainly have to settle for Platners. It's not a question of whether Platner is good enough, the question is whether Platner is better than Collins right now. While we lack the ability to elect good candidates, elections do little more than allow us to block the worst candidate.
When there are real options besides blue and red, blue no matter who will have outlived its usefulness. We aren't there yet.