Reply to post:

People keep getting born. That's where the trouble starts.

They grow up, and want to move out of their parents' home. But where to move to? Gone are the days (if ever) when they could just wander into the woods, or the wilderness, and build a cabin for themselves. All the land is already owned by someone. Mostly, by very rich (and therefore influential) people.

So they either have to pay whatever the asking price is for land this week, or resort to shenanigans. Option 1, which you'll note is only available to people who have quite a lot of resources to start with, helps to make the rich richer and keeps the poor in their place.

Option 2 is the beginning of "not getting along". (Although of course you can also use shenanigans to make yourself richer and then buy the land fair and square, thus combining both options. That's also "not getting along".)

Every war ever is ultimately about "who gets to live where". Putin, for instance, thinks that Ukraine should be populated by people who think of themselves as Russians, loyal to Mother Russia, and to that end he's trying to scatter people who think of themselves as "Ukrainian" to far-flung parts of Russia. (Or Europe, that works too, so long as they don't go back.)

Why is all this relevant to the GGP post? Because "Why can't we all just get along?" is hopelessly naive. It's something that can only be said with a straight face by a very young person who not only knows nothing about history or politics or demography or social sciences in general, but is also largely unaware that there is anything to know about these subjects. And so is the GGP sentiment: anyone who's spent more than about two minutes thinking about the subject already knows that it's not going to happen, and why. It falls under the heading of "aww, that's sweet" if the speaker is a teenager or younger, otherwise it's just irritating.