A language you already know has lower (real or perceived) friction than something you don't. Some people may hate writing Javascript (though some subject themselves to it voluntarily, see node.js) but they still write increasing quantities of it.
The same arguments could be made to PHP or Visual Basic and I remember people saying nasty things about the C++ WinAPI back in the day.
Unless you have the luxury of being Apple you don't really get to say "here's our blessed language , you will learn it" if you want to appeal to the masses.
Granted, hence why the GNOME devs didn't choose Vala. That doesn't explain why they didn't choose a cleaner, easier language, and it certainly doesn't explain why they chose the ass-end of web development.
> already know
The developers that Already Know only Javascript are not, in my opinion, the ones that GNOME will garner the most benefit in attracting.
The same arguments could be made to PHP or Visual Basic and I remember people saying nasty things about the C++ WinAPI back in the day.
Unless you have the luxury of being Apple you don't really get to say "here's our blessed language , you will learn it" if you want to appeal to the masses.