This is patently false. Many entitlements are locked behind explicit, human approval from the Apple Developer Program; examples include NFC with payment-related Application IDs and Multicast Networking. You actually have to submit a request that basically goes 'Please can I write software for this device?' to use that hardware on the device (see https://developer.apple.com/news/?id=0oi77447). You emphatically are NOT able to run 'whatever you like'.
However Apple can lock their software. The software is licensed, you don't buy that but licence it like Photoshop. Adobe also doesn't provide you with an easy way to do your taxes on Photoshop but I'm yet hear to claim that Adobe is preventing us from doing our taxes.(I couldn't think out of my head a major software that's not on subscription model, hmm)
Remove it and install something like Android on it, it is hard but it has been done before.
I simply don't see how Apple is obligated to make it easy or create tools for doing it. It's not promised upon purchase or on any advertisement materials.
It's not different than complaining that Apple does not let you use your phone as pocket heater through heating the Qi coil.
I know how unpopular this is but I will say it anyway, I can't stand it and I am willing to sacrifice a few karma points to convey the message.
I have distaste against the claim that Apple is not allowing people do something on their device because this is technically false. What Apple is not allowing is using its App distribution platform outside of their store rules.
What Apple is not helping with is side loading. They don't have a say on what you install on your phone but they have a say on what you can distribute on their App Store. That's why it's the developers that are suing, not the users.
However hard it is, you have all the rights to run whatever you like on your device you purchased. The "Apple doesn't allow you to install apps, you don't own the device" is a fallacy.
You can pay for the convenience(get a developer account, use the Apple toolchain to install your apps) or hack your device and run whatever you want on it and both are completely O.K.
At the time of purchase you don't sign anything preventing you from doing it, consumer devices are not like those developer devices that apple sells or send upon limited use or NDA agreements. You are free to do whatever you like to your device. Install a Chromium engine or blend it for YouTube views, it's up to you. You are only limited with your local laws, so dispose it's battery responsibly and that's it.