There are loads of these kinds of libraries. jQuery, Prototype, YUI, MooTools, Scriptaculous and Dojo immediately spring to mind. What will Google's do differently?
So I'm not sure what your point is ...
Shame they're not designed to make writing correct english sentences more simply eh?
"What's wrong with variety and choice in the hands of a developer? "
Well, for one thing, it means yet another library to learn and get used to. Have a search for web developer jobs now and you'll see many of them requiring experience with a specific library. Likewise PHP jobs. If you don't have experience with the framework (Symfony, Cake etc) an employer is looking for then you have little chance of getting the job.
Choice is good, but only up to a point.
I have no opposition to the library, if it is done properly (what's good for Google generally isn't so good for smaller players), but I do object to press-releases that claim to be the best thing since sliced bread AND first to market, when they are neither.
Another layer of abstraction is just not needed, it is so easy to build your own abstraction to fit the task at hand then bother to rely on some form of pseudo generalised abstraction.
So, what, reinvent the wheel with your own bloat just to fulfil a simple need? Sure, let's all start from scratch, why would anyone need to use a programming library?