The market is far from perfect, however. An economist would know that there are things called externalities. They are costs which are not borne by the entity which receives the benefits, or vice versa. Examples of that would be pollution, where the community as a whole might have fouled air or water, while only the owners of the company doing the polluting gain the benefits.
Government must step in when there are externalities to balance the costs and benefits. There are also instances where imbalances in negotiating power may lead to abuse of others. That's why we have things like OSHA, because companies may not "find it in their economic interest" to implement employee safety measures. That's why we had things like the Triangle Shirtwaist Fire where many people were killed.
Government must step in to make certain all the people are protected. Laborers may also not have enough power to insist on decent wages or benefits for the mass of employees. Government steps in with minimum wage laws, child labor laws, and the like. The market may also allow monopolies to form, which can result in great inequities for the greater mass of people, along with great profits for the monopolists.
Now the Friedman disciples would argue that the market, left to itself will resolve any problems. That only works when all parties have roughly equal negotiating power and when there are no externalities. Unfortunately all too often that is not the case. Perfect competition exists only in very limited and circumscribed cases, and not enough to influence the economy as a whole. Friedman dismissed or poo-pooed any idea of market failures, as do all of Friedman's disciples.
Most economists, unless their economics is driven by their ideology, know this all too well. Some folks speak from ideology and ignorance of economic realities, then choose to insult those who disagree, since they haven't the depth of economic knowledge to make reasoned arguments.
