You think that's bad?
If you really want to talk about breaking cross-compatibility needlessly....
Try dealing with arsehats that write shell scripts that start #!/bin/bash yet don't use bashisms, or even worse, scripts that start #!/bin/sh and do use (generally unnecessary) bashisms.
That's just one of many examples where Linux (Linux/GNU distributions, not the kernel) is a plague on the unix world.
I won't even go into the alsa/pulseaudio shite that came about because someone couldn't fix their broken OSS implementation...