He's the early incarnation of Andy Rooney or others talking about how dumb the American people are. Typical liberal thought where all the regular people are stupid.
If recognizing the inescapable average-ness of average people makes one a liberal, what sort of delusion makes one a conservative?
Mencken was a realist, a painful one, true, but a realist. He could never be called a liberal in any rational sense of the word. His love of liberty alone and his acceptance of the risks therein separates him from liberals.
They may have had in common a certain disdain for the average fellow. But that is absolutely as far as the comparison goes, IMHO. Rooney postures himself as some kind of great writer, but I have not seen the evidence, nor have I heard it said by anyone not on the CBS payroll. Being a grump and being a great writer is not quite the same thing.
I heard Rooney on a lengthy roundtable radio program reflecting on the end of the millenium. After a couple of hours, each participant took a few seconds to sum up the state of mankind as the calendar page turned over to 2000. Rooney took his opportunity to opine that there was nothing worthwhile on the Internet...that it was for idiots. It was not a joke, but he is.