I think the article stumbles onto something not mentioned alot, and that's the low vitamin level people have like Vitamin D. Which you get thru sunlight but of course is more difficult the darker your skin is.
That is the weird thing about COVID. It's well documented the flu attacks everyone about equally, but COVID seemed to specifically target the sick and weak or had poor nutrient levels. Not even age so much, there were plenty of people in their 90's and old who survived it without alot of symptoms.