I don't mean TSA or CBP literally. I am aware of the programs you are talking about. I'm talking about unofficial/soft-power policy that adds additional barriers pre-boarding for flights that fly into the US. You won't see this in the west/EU. I suspect it's more widespread in the rest of the world.
Some countries allow you to clear CBP on the boarding side, skipping it at the destination.
It's like Ireland/Dublin, Aruba and a few others.