There are other explanations for lack of vitamin D among the obese. Morbidly obese people are often homebodies. The most bioavailable form of vitamin D comes from the body’s natural generation of it from sun exposure.
People up north are often sequestered in their homes for months on end during the winter. This might explain why infection rates are higher in states/countries north of the tropic of Cancer.
If you saw that Harvard Health article I mentioned, it’s actually more like higher than 37° North latitude between the autumnal and vernal equinox. And 37° N. bisects much of the continental USA.
The darker a person’s skin, the more sun exposure they need to produce vitamin D. Hence black folks greater susceptibility to the virus and other diseases. Skin meant for the African sun.