Many of today's atheists aren't anthropologically, psychologically nor historically aware that most of their modern day morals are based on Christian contexts because of western society. Same with education and science. Anti-theists, who are the vocal ones on comment sections who probably don't know the difference of the word, are even less so.
Yes, there's been a lot of people who abused Christianity for power or perverted it to justify their deeds all through history. But those were people. Same for any ideology, many of which could just as easily be considered cultist. Politics are DEFINITELY not immune to it. It doesn't take much convincing someone of that unfortunate truth.
Still, the tenets of the faith are the basis for much of modern decency. Media and education has thoroughly failed for a few generations now. As they say, "a sign of the times".