Probably a byproduct on how hard COVID hit the more-populous states. All the emphasis in the first three months was how bad it was in New York, New Jersey, California, etc. It certainly was possible that those in more rural environments saw COVID as a heavy-population issue.
Combine that with rural areas being more conservative, and many people believing that wearing masks/social distancing was something only liberals did. This is basically what I think happened in North Dakota, my home state, and is probably why it currently leads the world in the number of infections vs. population size.
This is interesting. It gives a time/history of individual states' COVID rates, stepping through day-by-day since June. Each state's bar indicates its political bent.
https://dangoodspeed.com/covid/total-cases-since-june
Couple that, sadly, with less medical infrastructure in rural areas. Living in the Seattle area, I've got three major hospitals within 15 minutes of me, and massive medical resources within the county. Rural America has problems retaining medical staff (can't pay off student loans at a small country hospital) and the facilities themselves are smaller. So when it DOES hit, they can't handle it as well.
Ron Wanttaja