It's easy to see lies in people who disagree with you. To do so confirms your own world view without making you question it. It's much harder to look upon other views and say, "Some very intelligent people honestly believe something very different than me... some very intelligent people also believe as I do. What should I make of this?". I don't have an easy answer to that last question, but I'm also not looking for easy, convenient answers that require large portions of the population to be crazy, stupid, evil, etc.
It seems to be used to dismiss the entire idea being talked about. For example a liberal saying they want relaxed immigration asylum criteria, and a conservative says they're just virtue signalling, and thereby dismisses the topic. In that way it has become a sort of ad hominem attack. In fact it does a disservice to both sides of the argument because there can be very good arguments for strict asylum thay deserve to be considered but get masked behind such dismissive language.
I don't see a problem using the phrase as long as it isn't used to justify a failure to engage in an actual discourse or debate on the topics at hand.