I think you are misunderstanding the parent's point. The basic gist is that any glove, mask, and ventilator manufacturer should at the very least get immediate working capital loans/grants from the government to expand production.

Guaranteeing the sale means that the manufacturer will assume no risk for overproduction. The price would be whatever the prevailing market price was before the crisis or maybe with a slight premium.

In essence, the government should remove all business risk for manufacturers of needed equipment.