"We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America."

My posting quotes the Preamble. Promoting something is to facilitate it. The federal government is charged by those who form the government (We the People) to facilitate our  common good. Part of that mission in our 21st century culture is to make certain healthcare insurance is affordable. Otherwise it isn't available.