Surely the QANTAS decision is purely commercial. If a passenger contracts Covid-19 on one of their flights, especially if the USA is involved, they might be held liable. They would therefore wish to take all reasonable precautions against that risk: both because they wouldn't want anyone to be infected, and because, if they were, such an action would be part of a defence against accusations of negligence; again, a reasonable precaution against having their ass sued off.
Nothing to do with governmental over-reach, New World Order, Bill Gates, or the threat to our vital bodily fluids.