This just happened to me the other night.
I’m in a dispersed camping spot in a National Forest. It’s not crowded. I go to sleep around 9:30PM and wake up at 4:30AM to someone parked right next to me. There’s no trees between us and no possible way that they did not see my car.
As I drive out of the forest I pass dozens of empty spots.
This has happened to me twice. Who are the people who do this? There’s no rational explanation for it.
After rereading they do mention they’re at a campground. I focused on the ‘dispersed camping spot’ phrase.
The only conclusion I can come to is OP uses different camping terminology than I’m familiar with. For me ‘dispersed’ can have a broad range of meanings but always means ‘not at a campground’.