The assumption that humanity is broken is absurd. Humans in a natural state (a tribe of hunter gatherers) for the most part do pretty well albeit under difficult material conditions

By way of rebuttal, I refer you to the late anthropologist Napoleon Chagnon's work on the Yanomami – one of those very same "hunter-gatherers" you write of so fondly – and their predilections for extreme and horrifying violence against their women. For them, though, that level of barbarism is normal and justified.

Hunter-gatherer tribes are not necessarily peaceful by nature. They do not coexist easily with each other or with nature. They are not "noble savages", but violent and brutal warriors when given the opportunity. There is nothing particularly innocent about them.

It is not an "assumption" that humanity is broken – it is an observation of a very human condition, that we stray from any objective moral code and behave selfishly and cruelly to our fellow men. This is true across cultures, time, and space.

1st Animals certainly do have sapience. of a different sort though its not even that different than ours. If you doubt me, you need to watch a Crow Court. I've seen several of them over the year, the long and short of it. crows have a functional justice system extremely similar to those in the West with a prosecution, defense and proportional punishment. They even evince behavior that resembles remorse during trial proceedings On top of that New Caledonian crows scratch make tools.

There are other examples but animals dream. build , socialize and do all the same stuff we do just differently. The only area where there is a huge difference is mating.

Its comforting to think w are special in some way and while we are smarter, that is about it. Its a hefty advantage if it doesn't kill us but we aren't top of the food chain and in real terms, if it exists the divine apparently likes bugs as there are far far more of them.

We may have an afterlife, be reborn who knows but we as a species will live, die and go extinct same as everybody else.

#2 Christianity is good software for a high order culture . No doubt. This doesn't mean that its true. It also has a tendency these days to blame spiritual forces for human foibles. Malign spirits may well exist . This a again not the same as Christian cosmology nor should we assume that in most cases a spirit is involved since a basic knowledge of the human condition and our nature explains almost everything we do . There is no need for the edifice of sin to explain anything we do.

#3 The assumption that humanity is broken is absurd. Humans in a natural state (a tribe of hunter gatherers) for the most part do pretty well albeit under difficult material conditions. The Western assumption that out ways are natural or sustainable especially urban ones are dubious . Again Christianity is great software for this sort of thing but this sort of complexity is profoundly unnatural to us and adopting urbanization especially will have consequences,

4th Belief in reincarnation can lead to lassitude on a societal level but any misplaced belief system can lead to bad conduct

I don't think alternate beliefs will do much better at allowing more than a billion people will highly variable I.Q's and time preferences to live in someplace the size of India. Other animals evince symptoms when crowded , we will too.

Reincarnation is pure fantasy. Have you ever heard anyone that believed in it say their past life was worse? It's always something more interesting than who they are now.

There was a series on after life experiences that a priest (I think) wrote. He had several books spanning years of research. He learned more as time went on. For the life of me I can't find them, or the dude, but I read them all. The one fascinating thing was there were 10 things in common that everyone experienced – Christian, Jew, No faith, kids.

Of all my reading on the matter, you get sent back to your broken body (which heals) to fix whatever, or send a message. Not somewhere else.

I like your analogy, but being Catholic, we see spirit and soul the same. Whichever, your spirit has to be pure to enter heaven, as such you are sent to purgatory to purify your spirit, not back.