Perhaps you’re forgetting that Martin Luther King was a man, and as such stood to loose nothing by colluding with Judeo-Christian patriarchy. Anyway, clearly we can have Christian feminists — several who claim the affiliation have posted here — but the concept strikes me as unburdened with excessive reason, given that Christianity is the root of, provides the catechism for, and has enforced for millennia and continues to enforce with an unwavering conviction, a most brutal and violent systemic misogyny.1. spelling snark: martin luther king loosed plenty of things, including a big ol' social revolution, by "colluding." i don't want to get all third-wave and all, and i reckon that there are a whole lot of problems remaining for black women qua black, qua women, and qua black women, in the aftermath of said social revolution, and possibly lots of new problems emerging. but i think that, on the whole, said collusion -- a mobilizing strategy that worked at the grassroots when little else had -- was almost certainly a net positive for black women.
2. also: there was no patriarchy before christianity? christianity is a unitary entity? what? although it is always interesting to be told that up is down, black is white, and that cogito doesn't actually imply sum, i think it's pretty clear that i, a christian feminist, exist. and if i may be so bold: i am nothing if not burdened with excessive reason. please, somebody show me the logical proof that there is no possibility for feminism within a nicene-creed understanding of the divinity of christ, and we can all just go home. in the meantime, consider the fact that if you believe religion to be so excessively bound in patriarchy that it cannot be practiced in a feminist way, then you certainly must also renounce pornography of all kinds, most sex, and lots of classical philosophy.
i used to say that it sucked to be a leftist christian, but the lefties and the christians have both yanked their heads out of their asses w/r/t that problem in the last couple of years. seems to me that the last bastion of this sort of absurdist, reflexive derision is the feminist blogosphere (possibly the slightly-more-radical end of feminism in general). alas!