It been popular for 10 years or so, not just with the alt right. I like using it when pointing out soulless corporatism and hypocrisy.

Yeah, it seems to be another term for disingenuous but much more buzzy and maybe more political?

From the Wikipedia page:

Examples of behavior described as virtue signalling include changing Facebook profile pictures to support a cause, participation in the Ice Bucket Challenge, offering thoughts and prayers after a tragedy, celebrity speeches during award shows, politicians pandering to constituents on ideological issues

-- https://en.wikipedia.org/wiki/Virtue_signalling

Black Panther earned its success, as did Wonder Woman. Alt-righters who complain about them are truly lone voices. But there were two major movies in recent memory -- Ghostbusters (2016) and Star Wars Episode VIII: The Last Jedi -- that had unusually high RT scores that they may not have gotten if they hadn't been so on message. Doubtless the critics involved were trying to reassure everyone that they weren't one of those people. Had they spoken the truth and said, for example, that Ghostbusters (2016) was ill-paced, obnoxious, and mostly unfunny, the likes of Jezebel would have raked them over the coals and you know it. That's what they did to James Rolfe, for simply saying he would not see the movie.