There are two kinds of people in the world; people who believe "anti-theft" is a reasonable justification for this, and people who believe that this is just another tired "trade freedom for security" argument.
You'll rarely convince either side to change their mind on this. Its an issue that pokes at a really deep element of personal philosophy.
Here's my argument from the opposite side to try, however: Asking about how you can retain the anti-theft capability isn't relevant to the discussion, because sacrificing freedom for that, especially to the degree Apple does, is not worth any trade-off. This is the same right to repair issue that HackerNews, generally, derides John Deere for; the main difference, beyond Apple's psy-op level marketing, is that Apple hasn't pushed exploitation of this control as hard. But: They absolutely, undeniably do exploit many of the people within their system of control, not just indirectly ("the control is exploitation" is kind of a dumb argument), but very directly, between extremely high upfront costs, high repair fees, cryptographically refusing to allow third party parts, etc. Additionally: their self-control in pushing further exploitation is almost definitely a product of market success, because in the mega-capitalist system Apple lives in benevolence may be the result of culture or leadership, but it is allowed by market success, and denied during market failure.
A lot of that boils down to the original thesis; very fundamental personal philosophy. I don't believe, personally, that it is ethical for individuals or companies to do something unethical (non-negotiably asserting significant control over physical goods they sell) because it enables something ethical (reducing incidents of theft).
That might be controversial, which is fine. I think a point of that which is likely even more controversial is the argument that even asserting control over devices in isolation is unethical. I hope it isn't controversial, but I feel like it might be simply given the way the world is turning. That's a different topic of discussion; but in short, I think there's a strong argument that restricting freedom to independently modify and repair physical goods you purchase is a form of classism. Additionally, to turn the dial to 11 on this, that this assertion of central control has a very real, negative impact on national security.