We’re juggling several balls here. What you wrote is true. But it may not be the whole truth. What follows is a conjecture.
People with insulin resistance have very likely problems to store glucose as glycogen (https://www.ncbi.nlm.nih.gov/pubmed/18220643). Thus, they do have a different glucose metabolism – glucose has to come mostly from the blood, and if it isn’t there they get hypo. With the results from the study linked above that carb consumption may be beneficial if you have contracted a virus, this could contribute to a higher death rate because diabetics essentially can’t use carbs unless they eat almost constantly.
The keto effects are mostly from prevention: A stronger immune system and a better microbiome will make it likely that the immune system can fend it off. This will undoubtedly make keto people much more resistant to all infections. However, if the virus does multiply, then ketones may or may not be beneficial.
Bottom line: People on keto will be less likely to see an outbreak of the virus, but if they do, I’m not sure that they have better or worse chances than non-keto people.