I think the self-isolation part is key. If they're doing that as if they have Covid then I agree with you. And honestly, I think the commenters parents have a fair point about being in line with other likely Covid infected people.

There are additional outpatient therapies that can be medically indicated depending on symptoms, risk factors, and locally approved care protocols. Most physicians will only prescribe those therapies based on a positive PCR test. Some of those therapies include monoclonal antibodies (less effective now with the Omicron variant) or a brief course of fluvoxamine.

But for vaccinated patients with mild symptoms and no major risk factors, staying home and avoiding public testing sites is a reasonable approach.