Everyone has a theory about the President's COVID-19 diagnosis earlier this month. Here's mine. It's pure speculation. You were warned.
Put simply, if the rumors of the Bidens being blackmailed by China and COVID-19 being a Chinese bio-weapon are true, then we are dealing with Acts of War on par with starting World War III. I don't think it will come down to that, but that's the level of sensitivity that we're dealing with here. Obviously the White House needs to handle it with care.
What I think happened earlier this month is that POTUS went to the one place where reporters, White House moles, and compromised White House staff could be shut out without any uproar—the hospital. I think he went there for one final strategy meeting with his top military brass and trusted people before this all went down. And as for the rest of the White House who tested positive? Again, it's all about compartmentalization. It's harder for moles to get critical information if everyone is isolated or working from home. It was all just one extreme pre-caution to prevent WWIII and Deep State/Chinese sabotage.