Dude, it was old news even BEFORE the album was released.
And I don't know why it's so shocking, really. Plenty of instrumental-only bands have done the same thing...Hella, Irepress, Tera Melos, and etc. Some of it is a band expanding or outgrowing their sound, and some it's a band taking their gimmick and spinning another one off the top of it. Cuz really, what's more gimmick than an instrumental band? An instrumental band with vocals, of course!