I have a half hour to kill before my flu shot, so let's talk about the phrase virtue signaling.

What does it mean?

Wikipedia says: "Virtue signalling is the expression or promotion of viewpoints that are especially valued within a social group, especially when this is done primarily to enhance the social standing of the speaker."

Who uses this phrase?

Wiki: "The term is chiefly used by commentators to criticize what they regard as the platitudinous and empty or superficial support of socially progressive views on social media, but has also been used to describe analogous behaviour in other groups, such as pro-gun rights grandstanding among the American right, and by signalling theorists to discuss conspicuous piety among the religious faithful as well as agnostics and atheists."

From browsing PPD/TRP I can confirm the people I see using this phrase are alt-right, RP types and its most commonly said in response to someone making a moral judgement, "I would never do X, Y attitude is so backwards", etc, cue someone angrily responding with "ugh, more tiresome virtue signaling" and the conversation tends to break down from that point.

Why does it matter?

There are a few reasons I dislike this term, the first being it is often used to dismiss the original point in the laziest way possible; no rationale or explanation as to why the speaker disagrees, or offer of an alternative point of view. As I said above, this is the point where the discussion starts to break down, it's hard to carry on in good faith with someone who is being dismissive.

The second reason is, doesn't it seem just a wee bit hypocritical that many of the people who would use this term are also the type who think women sleeping around or being single moms is morally repugnant? We all have values, there is no one out there who is morally neutral without some idea of right and wrong. What varies between us is what we find moral or not. It could be said that every time a RP says how despicable single moms or sluts or women are they are signaling RP virtues to raise their status with other RPers. "Don't marry, don't commit to a slut, lift, maintain frame" = virtue signaling.

BPers are also dismissive

Some are, of course. They don't have a nice little term like virtue signaling to toss out, but it happens and its just as frustrating.

TL;DR: I think the term is lazy and dismissive, it impedes good faith discussion and ironically is used to signal "virtue" to the speaker's group, the same thing they're accusing the first speaker of doing.