For many reasons, but I'll admit it was mostly a provocative and clever remark more than an informative one.
If you want more meat than that: the US government, and in fact the majority of modern Western-style governments, do not directly control enterprises ("that's fascism/marxism/communism") but there remains a need for governments to interact and leverage infrastructure, information and capabilities of private enterprises - a need that can not be fulfilled by the blunt instrument of eminent domain.
Western style governments instead rely on coercion and leverage and also provide market advantages (and sometimes "Soft Power"; look that up) to achieve policy goals. The idea is then that governments nudge private enterprises to efficiently allocate their resoures for the greater good that individual customers and market pressures can't account for (because the calculus of a consumer doesn't include national strategy and because access to restricted information can't make it into the marketplace).
A fantastic example of that is the global cyberintelligence war, which the US and Five Eyes would very much like to win, and you should a tleask hope that we don't lose. [The vast majority of the Snowden leaks are about international espionage and sabotage (not about 'terrorism', the 2000's boogyman; find more in previous comments by yours truly).] There are other examples such as private enterprises with shared strategic interests having been invited to participate in international treaties like the Trans Pacific Partnership.
This has its own sort of internal self-consistent logic that is somewhat grounded in, although also represents a significant departure from, the ideas of Western 'Enlightenment' thinkers.
A criticism of this sort of leverage is that it has to grow more and more intense as the need, frequency, and scope of demands intensify due to resource exhaustion, accumulating expenses/promises, and competition with large centrally organized states and other Western-style states that are willing to interfere more to compete more (the 'prisoner dilemma' or 'tragedy of the commons' scenario). Every person you ask will give you a different answer on how much of this behavior, if any at all, has been happening.
The current conception of the state is that it must correct the market where it fails to allocate things efficiently (natural monopolies, etc) and that it may also collectivize cost where chance or circumstance have the power ruin individuals (providing emergency services during storms, snowplows during winter, equal access to education even for the poverty stricken) for the same reason people collectivize risk via insurance. But that otherwise it should remain minimal in size. I acknowledge there are debates about the concept of the state that would fill libraries. These are broad strokes.
States have learned that wielding private enterprises for both Soft Power (having the world rely on US company services or Chinese goods, owning water supply [Nestle]) and coercive power (withholding access to treatments and cures of diseases, manipulating social media to stir unrest, exporting favorable financial regulations via the WTO and World Bank [why BRICS made their own]) and by giving domestic corporations favors so that they can compete internationally (traditionally tariffs, huge tax subsidies (sugar), and recently information from the cyberintelligence war) as well as financial manipulations (manipulating currency exchange rates so that they are favored for export) enable them to achieve policy goals. Countries must participate if their competitors are, sort of like a cold war but without the existential threat of annihilation.
So states play a large part in the fluxuations of markets. Some of this is highly public ("Today at 9:00, China bans bitcoins"), but others are surreptitious.
In so many words: because it is 'invisible' and because it is a 'hand'.