But Apple don't see it that way. I am glad ports to older Mac hardware exist, but the walled garden learns better defences each cycle.
Mac OSX is a fine system, enshittification not withstanding. I'm not massively impeded in my desires to run what I want, given homebrew and other software suites. I'd just like the choice to run FreeBSD or Linux or whatever else people port.
I truly do not see any downside risk to apple in doing this. A small documentation cost, at worst.
I think modern systems are viewed as constrained platforms and the fear at a structural level is people doing interesting unconstrained things with then. For apple that's an opportunity loss: if ableton on Linux is better they can't monetise ableton on OSX as successfully, is about as bad as it gets.
Nobody sues dell or lenovo because a PC runs Linux and the bits rot.