Have you been tested? Every day? You can't confidently say you're not infectious when a large proportion of cases are asymptomatic, or very mild. By all means be gung-ho about your own life, but your rights stop at the point they risk other people.

this is like saying have you regularly proven that you are not guilty of crimes?

It is really not how it should work at all.

Assuming everyone is infected at all times is both absurd and most importantly unworkable and counterproductive. The net effect is the opposite of what it wants to achieve.

You will never be able to confidently say you are not infectious of some disease.

Exactly. Which is why, when there is an epidemic of a dangerous disease, measures need to be implemented that assume that everybody is infectious unless proven otherwise.

No, that's not the point. If the small risk of someone dying from covid19 is enough to take away everyone's rights, what keeps your state from taking away your rights for a similarly flimsy reason, such as the risk that you will commit a crime?

Laws, constitutions, the legal system, and the ballot box.

Mature democracies should have the ability to carefully and responsibly limit some rights in times of great crisis, such as wars and pandemics.

This is essentially the same principle that says restaurants have to follow health regulations to prevent spreading disease.

Yes, you do. It's honestly not that complicated.