Here's Arnold Kling:
...the principles of good intellectual debate are not that obscure. Just make arguments as if you were trying to change the mind of a reasonable person on the other side. I believe that the reason that we don’t observe much of this is that most people are trying to raise their status within their own tribe rather than engage in reasoned discourse. It’s sad that reasoned discourse does not raise one’s status as much as put-downs and expressions of outrage.I suspect this isn't new - much debate (and not just political debate) is tribal. I guess Jonathan Swift made the point well:
Whereupon the emperor his father published an edict, commanding all his subjects, upon great penalties, to break the smaller end of their eggs. The people so highly resented this law, that our histories tell us, there have been six rebellions raised on that account; wherein one emperor lost his life, and another his crown. These civil commotions were constantly fomented by the monarchs of Blefuscu; and when they were quelled, the exiles always fled for refuge to that empire. It is computed that eleven thousand persons have at several times suffered death, rather than submit to break their eggs at the smaller end. Many hundred large volumes have been published upon this controversy...The other day - seeing as how I'd received a gift of £25 on a plastic card - I was wandering round Waterstones. It struck me then that many of the books on display are designed to appeal to a fan club rather than to present an argument for all - from Naomi Klein's latest poorly-research rant through books on Brexit written entirely to shore up one or other side's argument to the kind of flag-waving certainty given to us by pop psychology, lifestyle and self-help writers. And don't get me wrong, this makes complete sense - once you've got a bunch of unquestioning fans, writing to appeal to them is clearly the best option (assuming you want to sell loads of books and buy a new house or maybe a whole island). These books are, however, akin to those 'many hundred large volumes' that Gulliver was told about.