I'll help you through this, as that simple observation seems to be quite a challenge for you.
1) I'm an Emacs user and enthusiast.
2) I look into a lot of videos about Emacs.
3) I've noticed that, recently, many of these videos and screenshots are by people using OS X.
4) Someone wondered about an OS X video on the Emacs site.
5) I pointed out #3.
People like you are why FSF supporters have their reputation.