I don't think you'll find anyone disagreeing with the notion that people can't just do whatever they want, that there needs to be some form of law.
But it seems you have something in mind that fewer people would agree with.
Most of the "checks and balances" on business is simple rule of law: You have to fill the terms of a contract, you must respect property rights, transactions must be voluntary, offers must be filled if accepted, you can't have banks manipulating the currency, etc. Some of this we're good about, some of it we're not. (For instance, I argue that our monetary system unfairly biases our economy towards fewer, larger corporations than would otherwise be possible.)
The "robber baron" article doesn't actually list anything they did wrong and by and large, the listed people ran businesses that dropped costs of then-luxury products. Rail transit, clothes, refrigerated food, oil, and steel all saw huge drops in price and cost, and resulted in the biggest increase in standard of living for the typical (median) person ever.