Doctors are always going to err on the side of caution, if it were up to them the entire country would be on full lockdown quarantine until there's a 100% effective vaccine.
When discussing these things you have to understand people like Fauci would rather there be nothing than anything, meaning, the contagion would be easier to deal with on a macro level if there is no activity whatsoever going on in the country.
Hearing from them they're always going to be overly cautious & highly alarmist, whether they are correct in that line of thinking remains to be seen, but they are simply looking at it from a health & hospital overrun standpoint. They just want to get it contained & to have less & less people being forced on the healthcare system, so if that means sports & everything else must be sacrificed in the process then so be it (according to them).
South Korea is already playing Baseball again, if America can't figure out how to continue organized live sports before 2020 is over then we've seriously failed as a Union. Covid-19 ain't going away until there's a cure, so we either need to shutdown for the rest of the year & go on a full Martial-Law style Quarantine or just accept the fact the virus is here to stay & move on accordingly.