This a just a personal observation which may or may not hold true across the board. I've encountered several blatant "virtue signalling" episodes at work lately and they have each followed a pattern.
Each time the initiating group has been the handful of young childless women I work with. They will suddenly raise an issue like Trump or Sonia Kruger and immediately step into group enforcement mode. What I mean by this is that if a man were to raise a political issue he might say something like "Hey, how about that Donald Trump guy?" According to his politics he may expect the others to say something negative or positive about Trump, he may even make it clear that he expects something negative or positive. But it begins with a relatively open-ended topic-raising comment.
But with the young childless women the intention from the beginning is very clearly to shut off any kind of discussion. It will be something along the lines of "Hey, what about all those dumbass Americans who support Trump. They're all stupid hicks. I've never met anyone stupid enough to support Trump. Everyone I know has basic morals." Then one of the other young childless women will pipe in enthusiastically in support and say something similar. Then another one.
The level of interest in thinking about the issue is zero. The level of interest in relating the issue to real world events is zero. The interest is, first, in signalling one's own virtue by holding to the "right" political views. But, secondly, I think it might also reflect young women enforcing social boundaries within the group and doing so in a way that I don't think would happen in an all male workplace (i.e. it is an expression of a certain kind of young female instinct to ostracise or "group patrol").
Anyway, after the young childless women have set the scene, a few of the younger apolitical men will join in, albeit more half-heartedly. So it is a case of the youngest, least invested, least experienced women leading men.
One of the difficulties in countering all this is that men like myself are more used to there being an opportunity to "make an argument" - but this is precluded by what happens at the very beginning. The expected entry point for argument never happens. What I have found works instead is not to directly oppose the virtue signalling but to simply raise for discussion something that undermines it. If the virtue signalling was "Sonia Kruger is bad/mad for raising concerns about Muslim immigration" I'll throw in something like "Hey, did you hear what happened yesterday in ......" It immediately switches the conversation to a real world event, which then begins to allow discussion, which then allows others (usually the older staff members) to voice their ideas.
What I am doing, I suppose, is to create an entry point for discussion that the virtue signallers are doing their best to avoid.
The women with children are generally (not always) more genuinely concerned with the real world effects of politics than the childless women. I don't know if this is because they identify more with the political concerns of their husbands or because they are concerned about the future safety of their children, but the distinction does seem to be there.