This is terrible advice that will kill people.

Here in Australia skin cancer (directly caused by exposure to UV) is the most common cancer[1] and kills an increasing proportion of people every year.

Sure, vitamin D deficiency is bad. But don't tell people who are spending all day in the sun not to wear sunscreen! Tell people who never go outside to get 20 minutes of sun a day instead!

As pointed out elsewhere, the primary argument ("how did we get through the neolithic age") is bunk - there is no evolutionary pressure once someone has reproduced, and almost always skin cancer kills people over 30.

[1] https://www.aihw.gov.au/reports/cancer/skin-cancer-in-austra...