The writer seems to be one of the older crowd that made being a Mac user a huge part of their identity in the 80s and 90s. In the 80s that was tied in with the Mac being a pretty superior computer only accessible to the wealthy. In the 90s the Mac became a bit of a disaster as the decade went on and these guy stayed in utter and complete denial about it.

Then when OSX (-> Mac OS) started becoming really great in the 2000s I think they complained about stuff changing but then felt recognized when developers started flocking over to the Mac. But then you've got all these average people jumping on buying iPhones and iPads and Watches and AirPods and now they don't feel special.

It is pretty hard for me to get worked up about it. Some of the glory days were nowhere near as great as they remember, it's just they were a special club back in the day and now they're not really. The rest of us will just keep getting our jobs done using Macs.

One other aspect is a lot of these people were not particularly technical and as such were pretty inflexible in their thinking. They often seem to have built up extremely rigid and complicated ways of wanting to organize everything on their system because they are the kind of people who are used to following an exact set of steps to do everything on the computer, and they perhaps learned that at great pain. So they become extremely sensitive to UI changes as they perceive any change they have to get used to as wrecking their perfectly tuned productivity.

As an example they get super upset about the finder. They seem to have frequently built up some really complicated way of using the finder and then will get really upset, whereas an even more technical user will just go update their script/macros/whatever in 5 minutes if something changes and not get up particularly bent out of shape. The guy (and I've only ever met guys in this camp) who gets upset is probably not building a script that would have saved 100x more time over the years.