The effects of religion on the actions of all people throughout history is without debate incredibly profound. Statements such as "everything is politics" fall apart because religion affects politics to a great degree. A study of human history that ignored religion would be as useful as a study of US history that ignored race. Old lines from the 1990s like "it's the economy, stupid" are no longer meaningful in 2025. Everything is bound up with everything, there is no problem we face today that is unrelated to multiple other problems.
Secular leftist atheists like me sometimes wish everyone's religious beliefs would just go away so that we could begin to be ruled by science instead of superstition, but that is an impossible dream. To build a new kind of global democracy, we will need to recognize that different people have different values related to human rights and social relations, and some of those values will be informed by their religions. "Cast down your bucket where you are" is quite relevant here, in the sense that there is no way for anyone to stop religion from influencing people's political decisions, therefore we must find common ground where we can.
Religion's creation
The source of religious belief in the minds of humanity is probably a deep need to believe that life has a purpose beyond continuing for the sake of continuing. Religion is also helpful for imposing a moral framework on what human behavior is acceptable. It's not a giant leap to speculate that most people probably behave more pro-socially if they think there are cosmic or perhaps eternal consequences for behaving in an anti-social manner.
What Cornel West said about religion and Marxism in 1984
Cornel West wrote a brief essay on the topic of religion through a Marxist lens, and his intent was to be as global as possible in his view and not write in a too Eurocentric manner. This is a huge topic whose discussion would not be exhausted in the pages of 100 books, so kudos to him for attempting to say anything meaningful about it in so few pages of writing.
Here is West on the topic of religious revivals:
"The major contribution religious revivals can make to left strategy is to demand that Marxist thinkers and activists take seriously the culture of the oppressed. This fundamental shift in the sensibilities and attitudes of Marxists requires a kind of de-secularizing and de-Europeanizing of Marxist praxis, a kind of laying bare and discarding of the deep-seeded Enlightenment prejudices that shape and mold the perspectives and perceptions of most Marxists. This shift does not demand a softening of critical consciousness but rather a deepening of it. It does not result in an anti-science stance but rather in anti-scientism (the idolizing of science). It does not yield an anti-technology viewpoint but rather an anti-technologism. Nor does it produce a rejection of reason but rather a specifying of liberating forms of rationality."
I agree not only with what West is saying here specifically about Marxism and religion, but also with the philosophical worldview he is espousing. In order to truly free our minds, we need to try to view everything from every perspective we can imagine. Science has improved our longevity amongst many other things, but it has also created terrifyingly powerful weapons that we seem unable to resist using on each other daily.
But is any religion capable of reigning in our inner demons? So far, at least in the context of war, the answer is no. Most major religions instill an attitude in their believers that their religion is the only one true correct religion. In many cases this attitude morphs into something along the lines of "therefore believers of other religions are less deserving of empathy", and then the out-group gets dehumanized further and further until all empathy is lost and even heinous crimes against them become acceptable.
Is world peace possible, and if so, how do we get to that point? I have no idea really, I don't think I can speculate much about a question like this without sounding like too much of a doom poster. All I will say on this topic is that in my mind, everyone needs to update their belief systems with all the knowledge we've obtained in the last few hundred years, try to find common ground with each other, and stop killing each other over religious and political differences.