Sumner was making an off-the-cuff point in class. This was not part of his deeper sociological work, or his political philosophy as such. He was merely trying to show that socialism invariably leads to totalitarianism - its premises lead there, even when its advocates don't want to go there - and that the idea of laissez faire is closer to anarchism than socialism. Oh, and by the way, fascism was a left-deviationism, part of the leftist movement. Benito Mussolini was a socialist theoretician and then turned nationalist, which put him at odds with international socialism, but kept his anti-individualistic, anti-liberal bent. Fascism meant, after all, a bundling together of activists, a collectivism of supporters of the total state - the "bundling" from the bundle of twigs, a "fasces." And Hitler called his movement "National Socialism." He was of the left. Pretending otherwise is something American liberal-progressives do to lie to themselves about the dangers of their own ideology.