Because it's based off of BSD and uses very similar tools to Linux, and because of brainwashing of the Apple cult I guess.
Overall, OSX is a piece of shit OS that is shit to work on. I lasted a year before I just gave it back and got a Windows machine, most unintuitive frustrating OS I've ever used. Sure the hardware can seem nice (if it doesn't break or if you don't need anything repaired or replaced) but OSX is trash. If you want to use something, use Linux, there are tons of good distros and all of them cater to the power user.