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.
I know everyone has their own relationship or lack thereof with religion, I've never really had an inclination for any of it, even that time in high school when I hung out with the goth kids who were into Wicca. While they're few and far between especially in the west where it's largely been subsumed with capitalist brainworms, I've still known a few people that try very hard to live by the precepts of caring about your fellow humans and if it gives them some solace I can't really get too upset about it.
On a larger level would it not have caused more harm than good though? I get coalitioning when it makes sense, but active endorsement and banning criticism in c/Christianity feels farther than that.
I mean that sub generally gets 2-3 posts a month, I know HB can enjoy their struggle sessions but I imagine people there aren't looking to invite debate perverts into the mix.