Other studies have pointed to higher risk for A and B blood types / lower risk for O blood types. That's much easier data to gather, since you don't actually ha

Other studies have pointed to higher risk for A and B blood types / lower risk for O blood types. That's much easier data to gather, since you don't actually have to pinpoint specific genes, just do a blood type test on people who get severe covid. For this research - just because you've identified a gene linked to risk, doesn't mean you can say anything about why or how that happens. We likely don't know much about this area of the genome - how it's expressed, etc. and so they went with the angle we DID know - that it's inherited from neanderthal. No doubt more research in this area will be done now that they've found a region of interest.