A society needs slaves in order to function, right?

Only a few hundred years ago, the widespread notion of most people was that a society needs slaves in order to function. Those who fought against slavery were "unrealistic", "idealistic", "unpractical", "utopian" and so on. People believed that those who were against slavery had to prove that society could work without slaves before slavery could be abandoned The burden of proof was on those who fought for freedom.

Not much has changed since then in essence. Still the burden of proof is on those who fight for freedom. Obviously nobody is arguing for slavery anymore but instead a lot of other restrictions are believed to be necessary in order to have a functioning society. Those who believe in these restrictions assume that their cause is justifiable by simply looking at the status quo. Those who want freedom need to prove them wrong, apparently.

Do we need slave in order to have a well-functioning society? No.

Do we need a state monopolized health care system? No. Do we need a government police financed with taxes? No. Do we need to limit the freedom of speech, e.g. against hate messages? No. Do we need government courts? No. Do we need anti-drug legislation? No.

I can't demonstrate how a free society looks like, no more than those who fought against slavery could, but I believe in the cause anyway. Its a principle - a moral principle.