But why is that? Surely it must be because these forms of oppression support capitalism; that is, the current form of capitalism is determined (in part) by racism, sexism and homophobia, while the current forms of these prejudices are determined (in part) by capitalism.
So that means you should actually be on Brian's side of the argument - by being racist, sexist or homophobic, a union is siding with the bosses, and so solidarity with the working class requires that we _break_ solidarity with such a union. Now, it's a difficult question in precisely which circumstances prejudice within a union amounts to a betrayal of the proletariat; clearly merely having prejudiced members isn't sufficent, while, equally clearly, an actively racist picket line would be. I don't know enough about contemporary US politics to be sure either way, but if opposition to gay marriage is a central part of contemporary American homophobia, it seems conceivable that, by opposing gay marriage, a union might set itself beyond the bounds of solidarity. --
"There are very few members of the establishment press
who will defend the idea that things like aggressive
flatulence, forced feedings of swill, or even a barely-
muted hostility on the part of the candidate would
justify any kind of drastic retaliation by a professional
journalist - and certainly nothing so drastic as to
cause the Democratic front-runner to cut short a major
speech because some dangerous freak was clawing at his
legs and screaming for more gin."
-- Hunter S. Thompson Tim http://www.huh.34sp.com/