> You don't better yourself by engaging in pointless squabbling

Not always, but it is at least always entertainment. If the alternative you would have chosen is watching a mindless movie then you're no worse off.

> and you don't enrich the other person or those around you by doing so.

It is inherently a solitary activity. You are right that the likelihood of a bystander gaining anything from it is nearly zero, but there was never any reason to think they would. It was never about them. Squabbling, as you call it, happens so you can learn about yourself.