In my mind, there are two pretty straightforward, first principles at work that underlay a lot of these items.
Many, if not all, negative emotions, at least while being experienced, directly diminish cognitive capabilities. A concrete example: when a person is angry, that person is more stupid.
Next: modern communication technology allows/facilitates/encourages negative emotions to be generated, travel widely, and 'stick' in the minds of more and more people.
As I said, there's a lot of good analysis, but I believe that these two simple things are the most responsible for 'stupidity expanding'.
I went out of my way to state these things briefly, because fundamentally I think they are simple. At the same time, there are mountains of nuances and relevant conditions surrounding them.
I learned to be suspicious of any posts that said things like "This should work!" instead of "Here are step by step instructions for what I actually did that worked for me under these conditions on this date." Things that work for Windows don't necessarily work for Macs. Things that work at one time, don't necessarily work at another time.
Sometimes there was just one little detail missing, obvious afterwards but undocumented and costing an hour or two of messing around to find. Sometimes I gave up on a promising solution (such as radicale) because I just couldn't find that one missing step. That's why complete documentation of someone's experience is so valuable for someone trying to recreate another person's success.
Here's what worked for me (on Jan 2019), a setup that used apache, DAViCal, postfix, dovecot on CentOS 7 in VirtualBox on macOS 10.14:
"Replacement of macOS Server: Calendar, Contacts, and Mail" https://7402.org/blog/2019/replacement-macos-server.html
It was broken by the end of year due to changes by Apple, requiring the following fix (as of Dec 2019):
"New self-signed SSL Certificate for iOS 13" https://7402.org/blog/2019/new-self-signed-ssl-cert-ios-13.h...
Good luck. It's satisfying to get one's own server working, but it might take on-going maintenance.
In hindsight it's probably better to spend the money on a hosted solution.
just the different i was looking for!