If that is true: There are about 1,500 Big 10 football players. I haven't heard any numbers, but suppose about 5% have tested positive. That would mean about 75 confirmed positives. If 10 of those have actual heart issues, that is 10/75. If the entire conference were to become infected during the season and that ratio were to hold, that would be around 200 student athletes with heart issues. That does sound alarming. But of course it is based on "reported" numbers of people with issues and estimates of how many are infected.
The overall point decision makers are trying to make is that this goes beyond infections and death...there's a lot of runway in the middle that could affect the long term health of an SA. There's still a LOT for science and medicine to learn about Covid, much of which won't happen for years. This is a disease that affects the heart, lungs, brain, nervous system, etc. It affects people differently, and scientist are still trying to find out why. You go back to the early days of this virus, and most of the assumptions would now look stupid (Anyone remember the virus was supposed to disappear during warmer months? How about if you had the cold or flu you built up some antibodies?). Worst thing for anyone right now is to make ill informed decisions that could harms these SAs for years...even worse, lead to death.
As I said earlier, from the POV of an SA, I want to see them play because they can't have this time back. Once it's gone, it's gone...the vast majority of them will not play in the NFL so this is it for them. If they lose just this season, that's 25% of their college career. If it bleeds into next season, that's 50% of their career if the NCAA doesn't pass Covid eligibility measures. That's like a 40 year old man losing his 20's or 30's...all of it beyond an SA's control. You have sympathize with these kids because they've invested most of their lives to play on this stage.
Tough all around. Decision makers are trying to do what's best for the players and the schools, medical experts want a safe environment, coaches want to see their players safe as well, but also want to coach the kids they invested time in, players want to play...and us fans want to see them play.