This is a new term to me but it makes a lot of sense. It seems to have begun in Britain where it has been explained well.
“The most savage, bilious, self-righteous rants are from people living affluent self-pleasing lives in comfortable homes, doing lucky and rewarding jobs with like-minded friends. What they are doing (I risk losing a friend or two) is “virtue-signalling”: competing to seem compassionate. Few are notably open-handed: St Matthew would need a rewrite of Chapter 19. “Jesus said unto him, If thou wilt be perfect, go and sell that thou hast and give to the poor. But when the young man heard that saying, he went away sorrowful, for he had great possessions. So he went on Twitter instead and called Michael Gove a ‘vile reptilian evil tory scumbag’, and linked to a cartoon of Iain Duncan Smith stealing a paralysed woman’s wheelchair. And lo, he felt better and went for a £3.50 caramel macchiato with some mates from the BBC”
Beautifully put.