Well, speaking as a hater
I'll give my side of the story.
As anyone who has seen my comments in the article threads can attest, I express an almost pathological hatred for all things Apple. I've been more than slightly acerbic in my opinions of "fanbois" and positively rabid about the doings of the company itself. I've copped my share of downvotes for some of my more irrational rants, but I have my reasons for doing so.
Firstly, I am very passionate about computers. They've been my life since I was 16 years old and got my first Sinclair ZX81 back in 1982. I was part of the Commodore 64 and Amiga demo scene and I've built my career as well as my hobbies on computers. I have no S.O., no kids, because the lifestyle choices I have made centred around computer technology more than people. That's my nature, that the passion most men give to their wives and children, I give to what I do and what I create with computers.
In all this time, I've grown up and lived with a culture of relative openness in computers. I've become used to the concept that a computer I've bought and paid for is mine, to do with as I please. And part of that is writing programs and sharing them with people. The feeling I get when I see someone using my software and knowing how it impacts their lives is awesome. Even more awesome is when I see someone expand on my idea or program, and they show me their improvements. That's been the way I've worked since the old demo swap-meets and copy-parties of the Commodore 64 days.
As you can see, these things matter to me. A lot. I've lived my life around them, and I have strong feelings about them.
So when a company like Apple starts locking down everything in sight, and by showing other companies that users are willing and even eager to have control of their own computers snatched away from them , those companies follow suit. You mention people going on about walled gardens and I can understand your frustration with the repetition, but for those like myself whose mentality was founded on building a greater whole on shared ideas this mentality is utterly repellent.
It's not only the app-store lock-in, it's things like the ability to reach in and delete software from your computer - a trend started by Apple, and quickly followed by the likes of Amazon, Google, and now Microsoft as well. It's all this corporate control-freak mentality that I didn't really see before Apple brought out the iPad. Yes, Microsoft was the tyrant du jour of the pre-Apple era, but even they didn't impose restrictions on the distribution of software - until Apple did it. And add to that the endless ridiculous lawsuits, where it's getting to the point where I'm almost afraid to continue programming in case I tread on someone's IP toes. I feel that I'm being told I'm not allowed to use my brain for what I do best because some corporation owns some vague general concept behind what I've come up with myself. And Apple, with their sue-everyone-for-making rectangles mentality, have come to exemplify this kind of control.
And I'm sorry, but that really, really, pisses me off. When I feel afraid to develop new ideas because "sorry, Apple/Google/whoever have the patent on that already", that makes me want to throw things and scream. But polite society understandably does not allow me to do these things, because the expectation is that we stop throwing tantrums somewhere around the second or third year of life.
So I vent. I let off steam. I rant and rave on a forum, to a bunch of people I don't really know and have never met. I do so knowing that some of them share in my anger, and knowing that others are angry about the same things I am is strangely comforting and soothing. I do so knowing that still others will be angered, offended or even amused by my rantings, and we'll let off at each other until you'd be terrified to leave us all alone in a room together. Yet if we all met down the pub, I really believe nary a harsh word would pass.
You see, at the end of the day, it's Internet rantings. And I believe that's why a lot of us do it. It's what psychologists call a coping mechanism - a means of anger management, a way of letting out pent-up frustration with the way the world is, in a manner that is essentially harmless, because only a fool takes everything you read in these forums (or indeed on the entire internet) seriously.
To my way of thinking, it's far better to explode all over a Reg comments thread with pathetic curses against "retarded fanboi sheeple", than to act like a complete ass in real life. That is why I sometimes carry on the way that I do, and I think it is a sentiment shared, if not always fully understood, amongst other commenters.