There’s the atheist joke that “Christians are announcing that without belief in Hell, they would be horrible people” or something to that effect.
Sad thing is that there indeed is truth to it, and it has consequences. As much as I dislike organized religion and on practical level, would align with scientific, materialist worldview, I do think that without straight forward “be good or be punished” paradigm, a lot of people will be exactly the kind of self-centered assholes we currently see in positions of power in the world.
Back in the day, rich people would fund hospitals and schools in hopes of getting to heaven. These days why bother, religion is mostly a cultural artifact to occasionally pay some lipservice to, while one fully believes that their material possessions are all they got, and even their lowest possible pleasures should be attended to with whatever resource they can spare. Scientific materialism helped get rid of a lot of assbackwards reasoning but with cold hard logic, came the ease of reducing everything to a number. Money, usually. Worth. Nothing else matters. You can’t put a number on love, care, kindness, or something as ephemeral as “goodness” - an ever moving target which is only ever defined by the person using the word, with luck at least slightly informed by (pro-)social contracts. Indeed most people would specifically reject any attempt to put a number on those qualities as it would run counter to their virtuous nature. Which just makes it easier for those with power to devalue those qualities entirely, and with power, build structures that lets them indefinitely get away with it.
Actually, they did that to avoid peasant revolts. Attaching it to religion was just a convenient way to keep the church on their side so the pastors and priests would continue to preach the traditional message: “don’t be violent against your oppressors, let God handle them and you’ll be rewarded after you’re dead.”
Without that regular, Sunday propaganda, revolts would’ve been much more common.
I think it is a bit of both. I value your insight - more often than people think, the actions of historical leaders were done to appease the rival powerstructures (e.g peasants) - but countless historical people truly believed religion and allowed it to influence their actions, as is the case today.
A modern example of this toss-up is the USA’s action in Iran. From how Hegseth talks, it’s like he’s a particularly ignorant religious zealot; it makes me think he’s doing it out of genuine religious fervour. However, you might tell me he’s doing this to appeal to the religious voterbase, which it seemingly is doing. But that shows that support for the war does come from religious fervour, because that’s a reason why common people (the voters) might support the action in Iran.