[Nebullis]

Foolish. A dose of radiation accumulated over a few days or weeks would not have the same effect as the same dose over a hundred million years.

Silly. That's precisely the point of the statement in the article.

[Physicist]

That's precisely the point of the statement in the article.

Then I don't at all understand what they are saying in the sentences I quoted. It certainly sounds to me that they are integrating the radiation dose over a 3.8-billion-year timescale, and saying that the result is too small (a totally invalid calculation).