I think if we were to unload the phrase (not that we can, these days - that ship sailed) we could use it to describe an expression of ideology that is not necessarily fraudulent or hypocritical, but lacking depth, passion or productivity. What does a "Free Tibet" bumper sticker do except announce your position?
But what I think is a mistake is the assumption that most people using the term make, which is that it is hypocritical, that people don't have a right to make their position clear unless they're manning the barricades. I don't think there's much point in a bumper sticker declaring your position on Asian affairs, but it's also not a sign of hypocrisy or wrongness by default. Similarly, I see a lot of "Black Lives Matter" flags and signs here in Vermont, where very few Black people are to be seen. They represent a real opinion, and one can at least hope they represent a trend toward real action. They do not require that the people flying the flags drop what they're doing and march on Washington.
It's become a right wing catchword phrase, like "social justice warrior," and the like, and I think it should be abandoned entirely, especially because everybody who has an opinion voices it, and any fool can call it virtue signalling. Wear a cross necklace? A flag lapel button? A bumper sticker? The people these days who are most wont to shout "virtue signaling" seem mostly to be the very people who see no contradiction in declaring the flag a holy icon, while at the same time displaying black and white and blue travesties of it, waving Bibles, and lecturing us all about sin in between sleazy affairs and secret abortions.
In other words, I think virtue signaling is pretty universal. Jesus told us we should practice our virtue in secret, but that he had to say it suggests that it has always been an issue. And certainly damned few Christians these days remember, as they loudly mouth the Lord's prayer, or seek to have it engraved in the public squares, the back story.
But unlike the thing itself, the use of the term is almost always, if not always, right wing code for what they see as hypocritical posturing of people they don't like, espousing things they don't like. Which of course means that for me, when I hear the term, I automatically assume that the utterance comes from a right wing hypocrite, arguing catchphrases in default of substance, and am likely to tune out whatever follows.