By your definition, a lot of the hardware that works on Linux is an "unsupported hack". I don't see why this even matters; if someone -- even if they are not the original manufacturer -- wants to support something, then by definition it is not "unsupported". Whether or not it's a "hack" or not isn't really relevant, and it really sounds like you don't understand the output of a good reverse engineering effort. If it works, then it works.
Hell, most Lenovo, Dell, IBM, etc. laptops don't have official Linux support from their manufacturers. They're also "unsupported". I guess that means everyone should just buy System76, Framework, or Purism, or one of the scant few models that a small minority of the big manufacturers actually support Linux on, right?
> Compare this to where people make a LineageOS release for their mobile device. Still unsupported by the manufacturer, but GPL requirements often mean there's still device code to work with, if not at least the device ROM being released that images can be used to boot another OS.
This is a pretty bad example considering that many phones with LineageOS support still require closed-source binary blobs since the manufacturers don't provide source for everything. If anything, LineageOS is more of a "hack" than the M1 effort, which aims to produce open-source drivers for everything.
> Apple is still one of the only hardware companies who have gone out of their way to prevent Linux from being run on their hardware.
I think you're ascribing to malice that which is driven by indifference. The things Apple does that incidentally make it hard to run Linux on their hardware are probably driven more by lack of caring than any deliberate effort. As marcan pointed out in reply to one of my other comments here, Apple does things because they need to in order to get the features, performance, battery life, cost, and security they want. If the "Linux friendly" way of doing things doesn't jive with that, they'll go their own way.
> As such, I cannot see why open source advocates would continue to try to get any distro running on Apple hardware
Perhaps you just lack imagination? Your motivations (or lack thereof) are not others'. "Open source advocates" do what they do for a wide variety of reasons. And the people who are working on this might not even be "advocates"; maybe they just like Linux and don't like macOS, but love Apple's hardware.