mostly propaganda.
I became leery when we sold a house last year and the same people running the testing company are selling the mitigation systems.
We ended up having only a negligible amount so it didn’t matter but if the buyers (who had ordered the test) pressed the issue I would have wanted to get another testing company (or two) to confirm the original.
With the reading I did at the time it seems that radon in the quantities we are talking about likely has little (if any) real effect on humans. That said the mitigation system is “only” $1000-1500 usually so if someone would rather be safe than sorry I don’t think they’re wrong.