I really don't understand how a few people seem to think.
Surely as consumers, and people who spend our money to buy something we then own.
We should all want what's best for us consumers.
I agree with you in principle that consumers naturally want what's best for themselves. The question then comes as to just what "best" really entails. There are over a billion active iPhone users in the world. It stands to reason that different people are going to have differing opinions on this matter.
IMO, owning what you buy is simply a means to an end, rather than an end in itself. Should the position really be that we must always own what we buy, or would it be more productive to discuss the respective pros and cons of each, and treat it as another set of tradeoffs to be negotiated in a product?
For example, you make a huge deal over owning the iPhone, yet countless people continue to subscribe to Spotify and Netflix and other streaming services, where you are basically paying for the convenience of accessing a set library of regularly-updated content. And of course, you own none of that content and will lose access to it the instance you stop paying. This doesn't make Spotify a scam. It just means that we have different value propositions.
There is also news of Nintendo possibly bricking Switch consoles if people tried to use them for unlawful purposes. Response to it also seems pretty muted so far. Either people don't care, or they don't think it's a problem that will apply to them because they don't intend to modify their consoles in any way.
If you told someone from years ago, you would pay a LOT of money for a product and then not be allowed to use it in anyway you want or do with it anyway you want, you'd think this was crazy.
Being able to "use a product in the way I wanted" didn't always result in the best user experience either (which is why I switched from windows to a Mac in 2011, went on to embrace the Apple ecosystem in its entirety, and have never looked back since). Android phones have had the ability to sideload since its inception, and mobile carriers used that "freedom" to preload all manner of third party apps onto our smartphones. Higher incidences of app piracy resulted in lower revenues for developers, which is a crucial reason why many of them tend to favour iOS (which is why I don't give much credence to the argument that the people pirating content are people who normally wouldn't pay for them anyways).
After all, it stands to reason that if it is harder (or impossible to pirate an app), more people will need to pay for it the honest, old-fashioned way if they want to use it, which in turn means more money for developers (and the iOS App Store does bring in more money compared to the Google Play Store despite having fewer users).
At the same time, being able to download and install malware from shady Facebook ads is not really a "freedom" I particularly relish either. This is why I (ironically) liken Apple to a union of sorts (I say "ironically" because I know that Apple has traditionally been opposed to unions), where I cede some degree of power and authority to Apple in exchange for their vision of what a better user experience means.
This doesn't mean it's perfect or there are no drawbacks. But as with many things in life, I recognise this as another tradeoff, and I an willing to give up the freedom of being able to access certain types of apps in exchange for a vibrant centralised marketplace. And here's the thing - a centralised marketplace only works when developers are not able to publish their apps anywhere else (which is why the Mac App Store has so few apps).
So back to your original point, I do not find the stance that "owning what you buy" is meant to be some sort of inalienable human right. Some want it, some will latch on any argument that paints Apple in a negative light (while ignoring that it seems to be the norm everywhere and conveniently giving those companies a free pass), and some just don't care.
Some people would no doubt prefer that the iPhone and iPad be more like a conventional PC where you get to modify and tinker with the system however you wish. But just as with so many times in life, this is a tradeoff, with its own bundle of pros and cons to contend with, and a more productive conversation could be had if only proponents of this would be willing to acknowledge the potential drawbacks and shortcomings, rather than continue to insist that there will be zero issues whatsoever.