Mhmm, and? I'm still waiting for the reasoning behind "they don't know any better" making it okay. So you think Aztec human sacrifice and slavery culture was A-OK? They didn't know any better either, after all.
Besides which, they didn't start out so cruel nor so isolationist. Since they're immortal and have no cultural turn over associated with the removal of prior elite rulers, doesn't that take your argument out at the knees? If they're capable of change in the one direction, they are capable of change in the other or they are evil, there isn't much more to it.
Why didn't the helots overthrow the Spartans. They outnumbered them more than 10:1.
Again with the moralist shit.
You seem unable to put down a big brush, in your rush to paint. Rather than "good" and "evil", consider the overall stability and features of the culture.
Eg, your choices about how they are evil, is no different from how an extreme Muslim state thinks the west is evil for allowing profane things like gayness to be in the open.
The features of by their culture exist, because they must, or their society would implode. Same as 1700s USA. Unlike 1700s USA, the status quo does not change, because the rulers are invested in it, and they never die.
Their culture stopped evolving in a broad way when they became immortal.
That is what you are not understanding
There is no uprising because it is not logistically possible, same reason the helots did not kill the Spartans.
In your haste to moralize, you are painting all the mound dwellers with the same broad brush. I tell you this is wrong, because it is the same as condemning the helots for Spartans brutality. Yet, you fail to comprehend. I tell you that the majority of the mound dwellers are clearly liberal, due to how they act, and you are confused because you paint them with the same brush as their elite.
The failure is still ultimately yours.