Dear People who call yourselves both Christians and Objectivists,
I spent literally over an hour the other day responding to the idea that being Objectivist and Christian aren't contradictory. It turned into, essentially, an essay outlining many of my own personal beliefs (which, frankly, are far from Objectivism) and how they fit with my personal interpretation and experience of Christianity. I think the underlying basis of most of what I wrote can be summarized in this way: I don't think that using every avenue available (including action by governments, from local to national) to help work towards a just, equal society for all entitles me to abdicate my own personal responsibility to help my neighbors (a category that includes... well, everyone). I think government can do many things to help the disadvantaged that I, as an individual, or even as a member of a church, can't do - things like passing laws preventing discrimination based on race, gender, religion, ethnicity, sexual orientation, gender identity, and age; things like using tax money to provide assistance, both monetary and non-monetary, for those who cannot afford food, shelter, healthcare, and other necessities for a decent life on their own.
(On doing some brief reading about Objectivism, I found that Ayn Rand sharply criticized altruism and self-sacrifice, which, as far as I'm concerned, are pretty key tenets of Christianity. And, actually, of all 3 main monotheistic religions, as well as many other religions... So there is that, too.)
What this really comes down to, ultimately, is that I think your philosophy on life doesn't actually match up with your professed theology.