In his classic book, The Road to Serfdom, Friedrich Hayek wrote about the ways in which the movement away from classical liberalism toward socialism threatens the advances that classical liberalism has brought, including individual freedom. When one seeks to order society from above, the refusal of those below to act as they must constitutes interference with the grand plan and must be, if not eliminated, strongly discouraged.
Becoming our brother's keeper - particularly when we are compelled to do so - implies that he truly be "kept" - not only assisted but directed to act in a way that facilitates our assistance.
Isn't the individual mandate a perfect example of this? The justification for this infringement upon the liberty of those who do not wish to purchase insurance is said to be the legally mandated compassion that will provide the care that they cannot afford.
The notion that people not be permitted to act in a way that makes it more difficult to help them has no obvious stopping point. For the left, compassion most often dictates restrictions on economic freedom. But might not social conservatives argue that compassion requires limits on self destructive personal behavior? If I am to be my brother's keeper, then I need to fight an aggressive war on drugs because they will frustrate - and raise the cost - of my efforts to help those who might take them. My brother should not have children out of wedlock. He ought not freely divorce his wife when there are children at home.
People will answer these questions in different ways but movement toward greater degrees of collectivism increases the frequency with which they must be asked. Obamacare is an extraordinarily ambitious effort to manage a large area of human interaction - to achieve better outcomes than its advocates think will be obtained through the voluntary interactions of individuals. It's not surprising that it requires extraordinary limitations on personal freedom.
Even if we avoid the temptation to micromanage personal conduct, we will inevitably be tempted to choose between deserving and undeserving objects of our compassion. While choices in life are inevitable and compassion can never be unlimited, collectivism centralizes these decisions. It tends to make them uniform.
It takes an extraordinarily sanguine view of human nature and of the capacity of elites to properly order society not to be troubled by this.