Did you look at what they were using to try to prove their thesis. I only looked at it for 2 minutes but it looked like they were trying to correlate populations that express the mutation more frequently vs. those that don't. With no other factors that makes a very weak case. With what we know from the science what should be expected with mutations more likely to get the virus, somewhat less likely to progress to severe. It's a bit of mixed bag because the lesser immune response would mean more viremia but also less chance of overreaction.