When speaking about free market, it is usually implied that war and slavery are banned. There would be no difference between free and restricted market otherwise, and this term would be useless.

Why would anyone support this? Local free market is good because allowing people do what they like gives them access to positive reinforcement so that they can improve at what they do and earn more money for the rulers. Global free market is good because it allows us to become super specialized and reach god-like levels of efficiency, more efficiency - more wealth.

Why oppose it? Rulers have no obligation to be clever, some people want to temporarily bend the rules to get to the top, others come into power through luck and can't keep it honestly.

Businesses, to keep their power, have to keep serving people. If people refuse to trade, no more power. Unless the state grants them a monopoly.

Governments don't grow by providing services, they either come from the outside and enslave everyone, or are initially formed by the people and grow more corrupt until they become like outsiders and enslave everyone.