What, if anything, can justify limiting workers' voice?

In most countries, citizens take it for granted that in the workplace, they have no right to a voice. They accept that workplace relations are hierarchical: bosses tell employees what to do, and all that employees can do if they disagree is to leave. However, for many individuals leaving is not a realistic option: they need an income and looking for a new job would cost more time and money than they have. So instead of speaking up, they comply with the conditions of employment they are offered. But is this justifiable? Why do we think that power needs to be held accountable in politics, but not in the economy? Why do the citizens of so many countries accept that workers, by and large, have no voice?