Why would there be demand for bonds that yield next to nothing? They become little more than a day-trading vehicle if there's no yield to earn by holding. Tax receipts pay the yield to bondholders. The economy is slowly shutting down if we stay on the current trajectory, which means greatly reduced tax receipts at some point in the near future. And especially since this "employer paid leave bill" will probably be enacted, the response from the private sector will be to cut employees instead of paying them to sit at home indefinitely after the first 2 weeks. Long story short, bonds quickly become next-to-worthless and pointless to hold since there's no labor/taxation backing them (the "full faith and credit") and no yield to earn by holding them. They go from safe haven status to worthless, quickly.
That doesn't even take into account the prospect of what helicopter money would do to the FRN, which are basically created out of the issuance of bonds at the Fed/Treasury level. FRN=worthless, bonds backing them=worthless.
