This is about Safari, which is not about preventing you from "running any code Apple didnt sell to you in the first place". It's about security/privacy.
>They are in a war against general computing
Well, general computing has many shortcomings that don't exist in computer as appliance. For some, the latter is better.
I might be misunderstanding you, but isn't this "security/privacy" argument basically "end users can't be trusted when it comes to installing extensions that respect their privacy, so let's get rid of potentially malicious extensions with arbitrary content blocking logic and enforce our single way of content blocking instead"?
Which certainly sounds like preventing the end user from "running any code Apple didnt sell to you in the first place".
Yep. Like "speed limiters" in cars. We could also trust car drivers "when it comes to observing the speed limit", but in many cases we don't, do we? And that's a mechanical limit imposed on top of fines for speeding and so on...
"But here they only hurt themselves" is not necessarily true. If you have family private data and they're stolen because you've installed a malicious extension, doesn't it also hurt your family? If your own data are then used to phish your friends, doesn't it also hurts them?
>Which certainly sounds like preventing the end user from "running any code Apple didnt sell to you in the first place".
Not really since:
(a) you can run many kinds of code (JS, etc) still in your web browser, can you not? Just not extensions with extra capabilities for sniffing, etc. So "only thinks Apple sold you" is not really accurate.
(b) the core reason is not profit, as the "Apple didn't sell you" part implies.