Question about evangelical political movement . . .?

Why is abortion and gay marriage more important than affordable health care and homelessness? This is a legitimate question and not an attempt at sarcasm. Based on the New Testament, if asked to locate Jesus the most logical place would be amongst the poor or sick . . . Most Christian liberals want to understand why these issues trump those of the disenfranchised. Again, this is not an attempt to launch an ugly debate . . . I want to understand the Biblical logic behind the movement. Thanks.