Yup control of the masses

Maybe that's a factor in the mix, but in reality, people sarifice their lives all the time for various causes, and the primary reason is empathy for a person or cause that they consider sufficiently noble (rational or misplaced, it doesn't matter). Soldiers are programmed to unthinkingly obey orders regardless of personal feelings, and this is done in a generic way that doesn't include religious indoctrination.

Other examples include taking a bullet or engaging in risking your life in some other way for your spouse or child. Most of us here would do that, with little to no thought about our mortality and the afterlife or lack thereof. It's not really bound up with that. It's protecting your tribe, the survival of your genetic material, or both. Religion of course gets in on the party (Jonestown, Branch Davidians, etc) but it hardly invented the concept.

By the way this well-documented and understood social phenomenon completely destroys the argument that Christianity must be / have been based in reality because people have been willing to be martyred for it throughout history. By that logic, the Jonestown cult must have been true, or a parent dying to save their child must represent what's really true. People give up their lives for reasons both ridiculous and sublime all the time. It is not connected to either belief or truth.

Belief in an afterlife is, it seems to me, one of the most hazardous ideas ever invented. If, in the mind of the Abrahamic faithful, a heaven or paradise awaits, what motivation remains to diligently strive to improve this world? If, as many believe, our lives are a ‘dress rehearsal’ and that our planet is little more than a ‘waiting room,’ what call to action to tackle the present will be widely recognized? Those who are the most strongly convinced that something much better materializes after death are, in my opinion, among the most dangerous of our fellow citizens.

It makes sense to me.

Yes, I've often thought the same thing.