To be sure, a lot of places off little to no PTO. They should, but it's not feasible in some circumstances. If an organization or company cannot provide PTO, then there needs to be some way for people to get paid time off if positive for covid.
I wouldn't wouldn't go into work, let alone lie to my employer about being infected, but, workers should not have to be in the position of deciding whether to work to take care of their families, or avoid working while sick.