[4ad]

If you want to use OS X, you need to play by Apple's runes. If you want to use some kind of Unix-like system, you don't need to play by Canonical's rules. There's a myriad of Linux distribution, not only Ubuntu, and then there are the BSDs too.

[coldtea]

So, in each case, you get to decide the rules you want to play with, by going with the OS that satisfies you.