Classic example being to take on $100k of debt to start a business and then paying workers $20/hour. Only one person is on the hook for $100k and they are rewarded accordingly if it pays off.
It's easy for the workers to then conspire about how unfair it is that the debtor isn't out there in the sun like them, but that's not a very complete picture of reality. Zero risk is part of the workers' compensation.
The argument (outside of Marxist circles) is more to do with whether business owners are being overcompensated because owners are able to exploit the market failures of the labor market--information asymmetry, power imbalances, quasi monopsony positions, government assistance for low paid employees etc...
There are also arguments about whether owners are being overprotected from risks by relatively recent concepts like limited liability (and more direct forms of corporate welfare), and arguments that workers aren't really in a zero risk position.