Which Friedman? Milton was an economist rather than a modern Republican and so said many thoughtful things. Like most leading edge folks, he wasn't right about everything but he was an interesting chap. Thomas is a guy who works for the NYT but my encounters with his writing led me in different directions so I have no idea if he is a Republican or what he says.
Krauthammer - okay. I didn't know he said such a thing so I guess there are such folks. It's the sort of thing traditional Republicans might say, so maybe he has some of that in him.
Or ...
The notion of taxing sales or energy might be construed as a means of reducing income tax. Not sure if that is the angle. Flat taxes and consumption taxes are not progressive. This is sometimes the underlying reason for an eccentric opinion amongst Republicans. They are artfully figuring out ways to reduce taxes on the wealthy and to plonk them on everyone else.
But heck, regardless of the motive, I like the idea of taxing gasoline.