Because your choice of hardware should be independent of the choice of software that you run on it.
This has been the world we've had since the concept of "IBM compatible" existed. Some people prefer Windows (because of available software, or ease of use) and some people prefer Linux (e.g. for efficiency, customisability or desire to run open source software). Why should that choice be tied to whether you've bought, HP, Lenovo or another manufacturer?
Apple has made some amazing laptop hardware, but Mac OS doesn't suit everyone. So well done to the Asahi Linux team for trying to take us back to that world of choice.
You still 100% should choose your hardware for Linux even on 'Windows' laptops.
Ideally it should run everywhere but in my experience you'll never get a positive Linux Desktop experience unless you tailor your hardware purchases to the Linux world - this usually means choosing a laptop that tons of other linux users are using, so the bugs are getting found and fixed, and documentation exists.
The key here is that it should at least run on the most popular laptop brands. It should run on Macbook Pro because it's incredibly popular hardware choice for software/technical people.
PowerPC was an attempt to standardize (at a least a subset of) the industry on a common RISC processor. There were even two attempts at industry standards for PowerPC motherboards (PreP and CHRP, the latter with Apple's active participation).
This has been the world we've had since the concept of "IBM compatible" existed. Some people prefer Windows (because of available software, or ease of use) and some people prefer Linux (e.g. for efficiency, customisability or desire to run open source software). Why should that choice be tied to whether you've bought, HP, Lenovo or another manufacturer?
Apple has made some amazing laptop hardware, but Mac OS doesn't suit everyone. So well done to the Asahi Linux team for trying to take us back to that world of choice.