Great post and yes, it's a serious issue in our sport.
I don't really have a good answer for you. I've had similar experiences.
I can only speak for myself but I found diving a lot less "political" when I was just learning. I made maybe my first 600 dives (first 10 years or so) blissfully unaware of the opinions of others. I had my group of friends, we went diving, we had fun.
Then I discovered the internet. For the first time I saw divers critiquing each others skills. It happened on un-moderated forums. Some good information was exchanged but there was a LOT of **** talking and a surprising number of threads devolved into discussions about politics and guns. In that time I certain discussion even ended in my receiving what I believed was a very credible death threat because I disagreed with someone.
Since then the politics have remained. I joined scubaboard in 2002 IIRC and the DIR wars were still smoldering. I think that the DIR wars did two things to our sport.
1) It made a large number of active divers aware of a new paradigm for safety and equipment configuration
and
2) It created a vast rift between like minded individuals.
DIR made arrogance OK. In fact, DIR made arrogance the norm in the mid to late 1990's. I would submit that during the DIR wars George Irvine was single-handedly responsible for alienating more divers than any other individual in the history of diving. He normalized arrogance as being equivalent to being right and he modeled a highly dysfunctional form of communication. The damage was severe in the least.
The flip side, however, is that he established, for the very first time, a coherent set of best practices in diving that we had never had before (or since).
The problem was that it was black and white. Either you were DIR or you were not DIR. At some point I even heard that "DIR divers never die, they just become strokes". There was little to no constructive dialogue possible between the DIR "community" and everyone else. To some extent this is still going on although the pressure on the community has been reduced a lot.
In my personal experience I was one of those divers who wanted to take the good and leave the bad about DIR, especially having come off the heals of the DIR wars. In my local community that was nonnegotiable. Conflicts arose as I tried to discuss the possibility of a middle-road and eventually I was labeled a stroke... "the UBER-stroke" because I dared to try starting a dialogue about it. I was ostracized and many very hurtful (and untrue) things were posted on the internet about me. This was the first time I really felt discriminated against due to arrogance. It was also the first time when I realized that scuba diving had been politicized by DIR.
Meanwhile on scubaboard we were locked in battle about "agency bashing". A new kind of arrogance had emerged, namely, which agency was best...... There were differences but people were making severe value judgments about those differences. I think the high point was when one of the directors (or soon to be directors) of CMAS came on scubaboard and posed as "just another instructor" and spent a year or more tearing PADI down.... while those of us who had any energy left corrected him time after time after time time after time after time time after time after time time after time after time
To no avail. This was the ultimate arrogance about agencies, if you ask me. GUE did their own thing and their message was not always easy to hear but this CMAS guy is the one who put the arrogance into agency bashing.
Thankfully CMAS directorate made him stop so at this point in time we have a PAX-SCUBA.
GUE is still doing their own thing. in DIR the politics are still strong but the best practices are much more accessible to the general public than in the past and agency bashing isn't being done at the executive level anymore....
To my way of thinking we had 10 or so bad years but that we are now profiting more from those years more than we suffer.
R..
The various agencies may be "profiting".
The dive industry is devastated. Sales down about 50% in the last decade.
Actual new dive certifications way lower.
Short courses, the rec/tech conflict, all have resulted in way fewer, and many under trained new divers.