All the above is a manifestation of the basic principle that if a number of people are gathered together, a certain proportion of them WILL be arseholes. The arseholery will take different forms depending on the nature of the 'gathering'.
With wikis and suchlike it manifests as I KNOW BETTER and THERE ARE RULES AND I AM GOING TO ENFORCE THEM. The crumb of comfort to take from the above experiences is that their behaviour probably reflects a gap or shortcoming in their lives which they feel they must address by wielding some scrap of 'authority' and sieze the chance to do a bit of what feels like policing.
I've had similar experience with Setlist.FM entries, including Genesis sets, where again people were simply being definitively wrong yet constantly de-correcting their wrong entries. One I wasn't directly involved in but amusedly observed was a battle between two guys who were adding and removing the '...' from In That Quiet Earth. Plus plenty of other wars of attrition on similar pernickety lines. I long since stopped contributing for precisely such reasons.
. Sad and funny at the same time... As you say, arseholery.
It's a like a fractal. No matter how much you drill down, there'll always be something people will disagree on.