WHY are there still twinks in my battleground

The matching system is in for 2.1; however it picking and choosing is fairly loose to match the amount of people playing in the battlegrounds currently. There simply aren't as many people playing now, from say when the new honor system had launched, and we would rather get players into battleground matches sooner than have them wait around just to match them with the people they were probably going to be matched with anyway. We'll be continuing to tighten up or loosen how stingy the matching is as the number of players in the battlegrounds increases or decreases, respectively.

Bottom line is that with enough people in queue you're going to see some better matching, but in the lower levels where there's generally already slim pickings the chance you'll see a twink every once in a while is probably pretty good.

Q u o t e:

So, why isn't this listed in the patch notes?

I would guess it's because the patch notes don't fill themselves in as we make changes.