Hardware and software have to interface at some point. When the people designing the hardware work at the company designing the software it's not unreasonable for them to come to some shared understanding of that interface which may not be standard, portable, or even publicly documented, and certainly not one that is stable.

This isn't incompatible with allowing users to install their own software. There just isn't an obligation on the original designers to make sure that software works. That onus is on the designers of that software.