Both protectionism and central banking are forms of privilege granted by the State to benefit a small group at the expense of a much larger group. We see winners and losers, i.e., those benefiting from the existence of the State and those losing from its existence. The "winners" are called the ruling class; the "losers" are called the ruled over class. From this it is not surprising that William Graham Sumner would eventually advocated for anarchism because anarchy means abolishing the ruling class. Apparently, he "came out of the closet" and declared to his classroom of students at Yale University that he was an anarchist! What I find to be very interesting is that Sumner associates anarchy with laissez-faire economics. Sumner appeared to be an anarcho-capitalist before the term was even coined!
I admire Sumner's courage for standing up in his class and speaking these memorable words:
Gentlemen, the time is coming when there will be two great classes, Socialists, and Anarchists. The Anarchists want the government to be nothing, and the Socialists want the government to be everything. There can be no greater contrast. Well, the time will come when there will be only these two great parties, the Anarchists representing the laissez faire doctrine and the Socialists representing the extreme view on the other side, and when that time comes I am an Anarchist.