Hmmmm. That’s interesting.
In some ways, I can see the vague sense that being a moderate comes with traits we generally think are virtuous. Though obviously with politics, most things don’t tightly follow those virtues.
Likewise, in some ways, I believe you're right. If we were to look at some loose, classical definitions of our categories:
1) liberal--emphasizes rights and individual liberties
2) conservative--emphasizes preservation of institutions, norms, with controlled, slow change when necessary*
3) moderate--sees value in both, perhaps seeking a middle ground that makes the most people the most happy
then I'd say two things. First, they all come with traits we generally think are virtuous. Second, the first thing entails that, as you suggest, being a moderate comes with traits we generally think are virtuous.
In the modern world--and I think this might have been your point in your last sentence--issues arise which are so far down the road on the first two that the third is rendered as merely seeing both sides, or maybe, not caring passionately about the issue at all. In other words, when 1 and 2 are miles apart, 3 can begin to range from "vague" to "nonsensical" when the defining characteristic remains seeing both sides of two fundamentally opposed views. However, value may certainly remain in the notion of seeking middle-ground solutions that make the most people the most happy. And even if seeing a few points from one side and seeing a few points from the other side constitutes a moderate position, I don't mean to suggest that's inherently inferior to either "side." I only mean to suggest it's not inherently superior.
I've just noticed a tendency of some moderates to believe their position is inherently better
because a potentially virtuous trait brought them to it, when I'd offer that there may be other virtuous traits which bring people to different conclusions (or the same virtuous trait brought them to a different conclusion), and so none of them can get an automatic leg up that way. It seems intuitive that being on the extreme end of something is "worse" than not being on the extreme end of it. I'm just not sure that's actually the case. Just as we'd want someone espousing the extreme side of an issue to back up what they say with reasons, and we'd feel justified in rejecting it if they can't, so should every position in between (moderate positions, perhaps) bear the same burden of producing reasons, and not be seen as better based simply on not being the extreme.
* That's not actually my definition of conservatism in its most basic, classical form, but I think it's probably a good working definition for many, and for our discussion here.