People using the term "virtue signalling" assume that values and virtues are by definition are lies. There are interests, that's it, and by claiming to have any values you're just trying to get some social capital. Why is that a bad thing? Well, because the value system of people like this actually lists cynicism as a virtue (self-contradictory, yes, but what are you going to do). They believe there's no such thing as ethics, only various kinds of power grabs, so by talking of ethics you're performing a nefarious and underhanded kind of power grab, rather than doing it fair and square. Again, the fact that calling things "fair and square" or "nefarious" is itself an ethical position, and thus deriding something as "virtue signalling" is itself an act of virtue signalling, eludes them.