There used to be a saying in the British Army's officers' messes that one never discussed "politics, religion and the memsahibs". You might laugh at that old-fashioned idea but, in a small society, it made sense to avoid topics that would create dissension, anger and bad feeling and disrupt the important cohesion of that small society.

I avoid most topics (BS) below the line except for one long-standing thread on old pocket watches. And I avoid them because, in many cases, the participants - and it tends to be the same participants - seem unable:

(a) to see any logic or reason in points of view other than their own
(b) to argue strongly without unnecessary swearing
(c) to argue strongly without unnecessary name calling
(d) to argue logically and in a reasoned way

Just my take on it. I can't think offhand of any argued thread I've read below the line where a participant has actually changed their point of view - and sometimes never conceded or recognised a single opposing point.

Above the lines may have had its ups and downs - but just look at it at the moment. Varied and reasonable threads asking for, and passing on information and ideas.

No contest.