It's not so much that other companies support Linux. It is that they support industry standards and protocols. Apple is totally vertically integrated and they always cut corners on hardware implementation to save money. This means their hardware does not work how it should and requires custom work arounds and patches if you want to run a normal OS.
This is very different from PC hardware. It doesn't need to support linux. It just needs to not cut corners.
Then again, the hardware that those companies release isn't quite as good as Apple Silicon, IMHO.