I don't get what all the fuss is all about. Why would you want to hide your identity unless you are writing something crappy or being a troll on Youtube or Play Store. A single sign-on service is a great decision and that't the way things should be when you have multiple services from same company. You guys don't mind using all services like Spotify, Quora etc that are so closely tied up with Facebook login. But when…
Try thinking this through. If necessary try to imagine what it's like in others' shoes. Please try to grant this the critical evaluation it deserves.
Agreed, there are some concerns as well. But again, aren't we living in an age where all our data is being sold to marketing agencies and companies. FB has been doing it since ever.