I buy it. It's all so innocent when the signaling is like Trekkies or coin collectors going about their business in a way you or I can't and won't understand (sure, I have no idea if you're a coin collector... Just making a point). But when the in group/out group phenomenon becomes a political philosophy, the responsibility rests on the in group to consider reality in their thinking. The exclusion of facts in a political philosophy is pretty much exactly the basis of Stalinism. There's a reason it was only high power party members who were subjected to the show trials. It was about making sure everyone knew that reality was whatever the Party decided it was on that particular day, irrespective of what it was the previous day. We're literally in e situation now where people can trot out Nazi slogans and then get pissy when someone calls them a Nazi. And it's not harmless. People are suffering because of it.