They are useful for blocking the obnoxious sounds that modern life impose upon us. The largest consumer hardware chain in Australia, 'Bunnings', plays a notice over the store loudspeakers regularly (perhaps every 15-30 minutes) warning that violence against staff will not be tolerated.
I'm not in any way an anxious person, but for some reason, the constant suggestion that I'm in a place where violence is a risk makes me feel upset so much that I don't visit my local store without my noise-cancelling AirPods.
I think packetlost knows that. I think the argument being put forward was that "if you are the kind of person that thinks that speech is violence, then you would believe that allowing someone a platform..."