I don't know what an "old-style leftie" is. There is nothing "old-style" about the Spartacist League and the Maoists, whose hatred for gay liberation, black nationalism, feminism and environmentalism has little in common with the classical Leninist approach. Lenin would have been a big fan of Malcolm X. He also would have been in the forefront of the struggle to drive back violent attacks on gay people. Although all these tiny sectarian groups of today like to throw the term "vanguard" around, there is only a single mention of it in the entire body of Lenin's writings and that is in What is To Be Done? In defining how a "vanguard" should function, Lenin holds up the German Social Democracy as an example:
"Why is there not a single political event in Germany that does not add to the authority and prestige of the Social-Democracy? Because Social-Democracy is always found to be in advance of all the others in furnishing the most revolutionary appraisal of every given event and in championing every protest against tyranny...It intervenes in every sphere and in every question of social and political life; in the matter of Wilhelm's refusal to endorse a bourgeois progressive as city mayor (our Economists have not managed to educate the Germans to the understanding that such an act is, in fact, a compromise with liberalism!); in the matter of the law against 'obscene' publications and pictures; in the matter of governmental influence on the election of professors, etc., etc."
In actuality, it only confuses things to use academic terminology like "identity politics." Let's use a simpler and more descriptive term: democratic struggles. In bourgeois society, there have always been groups who have not had full rights. Lenin was preoccupied with the democratic struggles of oppressed nationalities, but the general logic could be applied to gays and women as well. Struggles for self-determination or equal rights under the bourgeois system have a tendency to become class struggles in the epoch of imperialism. Socialists support democratic struggles not only because they are just in themselves, but because they help to mobilize people against the capitalist system. This was the logic of the black nationalist, Chicano and American Indian movements of the 1960s and 70s. In every instance, frustration with attempts to gain equal rights under capitalism led to a criticism of the system itself.
Louis Proyect
(http://www.panix.com/~lnp3/marxism.html)