I can believe you've never met them, but there they are. And they don't outright say they "like walled gardens" or something like that, they just love everything about the walled garden experience the iPhone provides them. You can even spot some of them in this thread, they
want Apple to decide how much privacy they have, they
want Apple to control and vet every app they install, they
want Apple to limit what other software can do on their devices in ways that you can't limit in open platforms.
And it only matters when it's backed by a purchasing decision. Someone can swear up and down that they hate walled gardens a lot but words mean nothing; if they turn around and purchase an iPhone over the plenty of open alternatives, it only signals that either they don't know what a walled garden is or they care about other stuff far more. Actually paying money for something cuts through all the bullshit consumers say to their friends or the internet about what they really want and what their priorities are.
Markets don't give each individual consumer precisely what they want, they give large groups of consumers what they want weighted by consumer priorities. In that way, most consumers get what they really want. Obviously that means some consumers don't get what they want and perhaps that's you, I don't always get what I want either. But sorry, if most consumers really wanted a device without a walled garden, they wouldn't have willingly and repetitively bought iPhones over more open devices. If there were a large consumer group of people that really want a good device without a walled garden and are willing back up their desires by paying for one, businesses will be aching to take their money. In fact, there already are many open alternatives that serve these people well. According to you your iPhone has issues even though you own one, but evidently these issues are so minor that you won't even give alternatives your money to avoid them. "But I really don't like it" is worth as much as it cost to say that, which is absolutely nothing.