Facebook stops supporting webkit browsers

Facebook:

You’re using a web browser we don’t support.
Try one of these options to have a better experience on Facebook.

Facebook stops supporting webkit browsers. That’s a bold move, which I don’t understand. Yeah, Chrome is made by Google and they are not best friends with Facebook, but Chrome recently became the ‚most used Web browser‚. Besides, the webkit engine is great in any regards.
So does anyone know something about that move by facebook?

Update: Okay, I might have gotten that wrong. Facebook isn’t saying that they stopped supporting webkit browsers – but they definitely don’t recommend using them either, which is still awkward.