As the CDC said above, absence of symptoms is not a sufficient indicator for a vaccinated person. If a vaccinated person is tested regularly, they can self-isolate upon a positive test result, since they can't rely on symptoms as a signal.
Absence of symptoms is not a sufficient indicator for the unvaxed either, so your argument falls apart.
Why isn't 90% reduction in ICU occupation and 70% reduction in chance of infection a sufficient argument for the public benefits? Just because it is not perfect, you'd rather let the country's hospitals overload and shut down?
In any case, vaccines don't really change the equation here. Testing for temperature and symptoms with COVID have proven to be ineffective because asymptomatic transmission in the early stages is a thing with COVID-19 even without vaccination.
I'm not sure that people who have chosen not to get vaccinated by this point are going to be the people who follow self-quarantine rules well.
That leaves the subset of non-immune people who are unvaccinated. If this hypothetical person is reckless (as your comment suggests), should they not have already been infected in the past 18 months? If they were not infected in 18 months, that suggests at least some ability to isolate and self-monitor.
> The agency now advises that vaccinated people be tested for the virus if they come into contact with someone with Covid-19, even if they have no symptoms... “Our updated guidance recommends vaccinated people get tested upon exposure regardless of symptoms,” Dr. Rochelle P. Walensky, the agency’s director, said in an email to The New York Times. “Testing is widely available.”