Exactly what the title says, Christianity in all its various strains still stems from the horrendous old testament, and with all the awful shit that endorses, as well as with things like Calvinism and the general doomsday cult foundations in the religion, why do some people still act so charitably towards it? Christianity has proven itself to be a morally corrupt and oppressive institution at every turn. Or maybe I'm just too negative? 
EDIT Ok guys I get it this was rather reductionist, and I definitely was disregarding all the good that religious folks have done, and that religion has inspired people to do, but again over correcting into enthusiastic support for religion can also be problematic.
We don't defend Pol Pot, Ceausescu, etc; and we don't give up on Communism because of a couple abuses of power, even if they caused lots of bloodshed.
We prize the ability to distinguish between a movement itself and specific cases of institutions that spring up from it.
Pol Pot, Ceausescu, and progressive Christians are all outliers in their movements.
Fair enough, I definitely let emotions get to my head with this one. Sorry yall.