Because it's open source and most of the applications for it are open source. That means you can compile it and the applications specifically for the hardware you have.
Windows does kind of support ARM on its specific hardware, but it can't be adjusted for other hardware and they have to translate most applications to work. Apple has done much of that work for their hardware to work well, as well as very good translation for x86, and because they leaned hard into the transition, developers were mostly forced to compile for ARM going forward. Microsoft hasn't done the same, and ARM is a tiny target, so it doesn't happen with any regularity there.