When did "virtue signalling" become the de facto insult against people standing up for human rights? I've been seeing it a lot around hacker news and from vario

When did "virtue signalling" become the de facto insult against people standing up for human rights? I've been seeing it a lot around hacker news and from various alt right outlets. I've seen it exclusively in dismissive tones to imply that advocacy only exists in a performative dimension.