That's true. But if left communism is to concede that class consciousness does not develop evenly and a vanguard is a political necessity, doesn't it also make sense to say that class consciousness develops differently depending on the socio-political realities of oppressed workers?
I think it does. It is one of my personal irritations with leftists that support national liberation movements despite a movement being dominated by "Islamofascist" groups, or other reactionary political movements. While the left communist criticism that any such liberation attempt will be incapable of circumventing capitalist imperialism are perhaps valid, I certainly think that it is also important to point out that these sorts of political movements will be an obstruction to class struggle in that they are a step backward from bourgeois liberalism.
Marx certainly wasn't shy to praise American and British democracies as being potential tools for the working class. He supported Lincoln and the abolitionist movement because "as the American War of Independence initiated a new era of ascendancy for the middle class, so the American Antislavery War will do for the working classes." Do you think that the destruction of free speech, rights to assembly, bourgeois democracy, etc. are irrelevant to the working class if they are to be replaced by fascism?