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.
There's also a myriad of ways it is not. You won't find a less dialectical materialist analysis than the sermont on the mount
i'm just saying, with the situation the left and the world is in, and adding historical experience, i think it's counterproductive to dismiss religion flat-out (or rather engage in pointless fighting around it, we don't have power to change it, and religions have some affinities we can draw on, depending on religion/means of production development/society safety nets as they are/depraved profit seeking stage)
It is valid to highlight the good done by Christians and the ways in which Christians can support and be a part of a socialist project, but I don't think it's necessary to pretend that the new testament is inherent socialist to do so.
i'm saying socialism bears the mark of christianity (either by emphasis or by negation), not the other way around tbh. plus dialectical materialism doesn't inherently contain ethics or morals, people just input their own.
i'm absolutely whatever on people hating christianity due to their own horrible experience, that's fair enough, just as it's fair for people in shit situations to embrace it. dismissing it however, as non-productive/non-compatible with our goals, is judging by history, not a great idea. *it's non-compatible with feuerbach religion development which marxists typically use (i think its feuerbach?) and thus with ontological view in general, but compatible with goals with some shenanigans on emphasis, same as anarchism tbh.