People have been criticising Apple for as long as I can remember (looking back, I recall the iMac initially being mocked for not being a "real computer", then the iPod being derided by people wanting a newer iMac instead, then the iPhone criticised by people wanting another iPod or Mac).
It may not be youth or ignorance, but something is making these people extremely cynical about Apple and incapable of evaluating anything Apple does objectively. Right now, one theory I have is that Apple, being a design-led company which claims to be at the intersection between arts and technology, continues to be misunderstood. It's like so many people have been conditioned to judging tech products based on quantifiable metrics like processor speed, amount of ram, number of pixels, physical capacity of batteries etc, and then Apple comes in and completely upsets conventional wisdom by showing how design matters in the mass market where the customer is the end user, and is completely free to choose a product based in intangible factors that cannot be measured, such as the look and feel of a device.
Maybe you can shed some light, given that you have been using Macs for 15 years more than I have.
Your analysis is spot-on. There a lot of unhappy/cynical people out there. The reflexive cynicism often expressed here started with the release of iPod and has continued with almost every product since (iPod, iPhone, Apple Tablet, Watch, AirPods, etc). All projected flops.
I think many people are just intrinsically unhappy, and taking a swing at the Man (Apple) helps them feel better.