This is false. You can create conditions where their only real choice is to work for you. And since they’re starving, they’ll work for very low wages. You sell the product of their labor and collect the surplus value created by their work.
The majority of the Chinese immigrants were male, many having left wives, mothers, sisters, daughters, and future spouses at home in China. Foreign miner taxes in California, often aimed squarely at Chinese immigrants, prevented them from staking mining claims, which in turn forced them to look for opportunities elsewhere.
The CPRR hired an initial group of 50 Chinese workers that in short time dispelled the negative assumptions held by some CPRR managers. They fostered a reputation of strength, efficiency, and reliability. More Chinese workers would be hired and they held a variety of jobs: laborers, foremen, contractors, masons, carpenters, cooks, teamsters, interpreters, and medical professionals. Even so, racial inequalities persisted. Chinese workers were paid an average of 30% less than their white counterparts. They were segregated in work camps and had to pay for their own lodging, food, supplies, and equipment.
The disparity came to a head on June 24th, 1867, when all Chinese railroad workers from Cisco to Truckee, California, a 30 miles section of track, stopped work.
Confrontation, Threats -- and a Bloodless Resolution
After a week's worth of lean rations had settled upon the men, Charles Crocker returned to the work camps. He dictated the options as he saw them: wages and hours were immutable. If the hungry Chinese workers returned to work immediately they would only be fined, but if they continued on strike they would not get paid for the whole month of June.
Motivated by malnutrition, most men agreed to return to work
And in a truly free market you can buy unicorns because both only exist in fantasy land. In reality there is always some government rules involved that shape the market.