That's not how a discussion forum works, you are describing something more akin to a structured debate.
Yes, that is what you said you wanted. A reasonably argued meaningful debate free of name calling, stereotyping, and gotcha digs and insults. Can't have it both ways. Well some have the discipline, but many do not. A free-for-all board hashing contentious issues just alienates and entrenches. Its a substantial reason social media is implicated in furthering division. Forums like this one, face that fact at some point. Either you limit the topics and establish behavior rules or you accept becoming something biased something that retains only those who like echo chambers. Honestly Simon this site has long ago crossed that line for many posters. Many of the past best posters left because of the constant caustic politics. You know that.
If we took a vote, I'd bet even those still here would prefer political discussions be limited to one section and not allowed to creep into every topic.