It’s not even an attack, it’s just what he believes. The core of “liberalism” is that most people are ignorant, toothless, yokels who need to be told how to live every aspect of our lives by the ruling class for our own good. This is not a “gaffe” or an “attack” that the Republican need to try to pin on Hichenlooper and Udal, this is just the core of their political philosophies.
Unfortunately, you are right, and I stand before you, reminded of their chief flaw - a total lack of humility. The biblical story of history’s first two brothers can be interpreted in that same light (lack of humility). Today, we see it in people who claim that any disagreement with the current administration can only be interpreted as racism. And that is the most generous interpretation of their actions.