So you believe there's a threshold. Back when I was studying this, I remember also feeling strongly that this should be true, logically.

Reminds me of the old (possibly apocryphal) story of the guy who dropped his banana from lunch on the floor of a nuclear power plant and it triggered alerts on people's dosimeter readings 😄

Natural sources are easily high enough to matter, a lot, with LNT. So yeah i agree it's probably just wrong, and 'ALARA' is ... not even wrong 😄