I don't believe that there are a lot of known facts, just a lot of speculation from very smart people. This disease is less than a year old. And these smart, educated people disagree. I was very leery for any football being played, before I heard what the U of I was going to do (daily testing, anyone with a fever not participating, etc.) I do believe the players are safer playing/practicing football than going to class. The regular students are getting tested twice a week, still way ahead of the rest of the universe. The campus is going to be on some sort of lock-down, need negative test within 4 days of coming to campustown. The difference here, the admins can say, we wanted not to play, the players and families came forth and wanted to play. Their hook just became easier to get off. Also, when the B1G was announcing, there was an assumption that this was the direction that the whole NCAA would go.
And, as a parent of a U of I student, getting tested twice a week, I want her going to in person class as soon as she can. I believe it benefits her college experience, which is one of life's biggest experiences.