It's weird you think you're making an argument there.
The problem is that radiation effects at low doses are very difficulty to detect. They could be very bad per unit of radiation and we could not now rule that out.
You're assuming that an unknown risk is _worth_ spending money on to regulate. Don't know if there are boogey men, better protect against them. Costs be damned.
I'm also surprised that others were quick to shoot the hormesis messenger. This is very well established mechanism of action.
Priming DNA repair pathways acts as a protection from further exposures.
However, and this is my take -- there are people in the population that are more sensitive to the sun. These same people are probably more sensitive to ionizing radiation, LNT protects all, including the most sensitive. That being said, it's taken to an extreme, and allows for sensationalism and fear mongering.
LNT is lawyer science, low dose radiation risk (cancer induction) is stochastic. There is already a high prevalence of cancer in society. To protect against possible litigation we eliminate sources as a possible induction points.
However, iff you developed a radiation induced cancer there's very little way to determine if your (mulitple) DNA errors were induced by cosmic rays or that time you walked past a bucket of naturally occurring radiation or due to those flights you took from Colorado to Brazil.
The dose makes the poison, we protect (and waste inordinate amounts of time and money) against low levels -- because we're ignorant to the precise pathways of cancer induction.
The problem is that radiation effects at low doses are very difficulty to detect. They could be very bad per unit of radiation and we could not now rule that out.