Identity and citation has to be discoverable -- that's part of the deal, the BY in the CC-BY-SA. But it does not follow that citation should be obvious. In fact, there are many reasons to do background citation.
First, citation on small pages is simple, but as pages get complex the burden citation places on the reader is non-trivial. Tell people many named people wrote a thing, and they will spend too much time figuring out who is what. It doesn't matter, mostly.
More importantly, obvious citation makes people hesitant to edit pages, because it creates the sense there are "owners" to the page. This is a pattern that was observed from the very first wikis. In fact, Ward Cunningham left much (most?) of his work on WikiWikiWeb unsigned, because he found people would be hesistant to edit his work (but they would edit the work of an Anonymous Coward more easily.
Here you edit the work of the beige square, or the red one. Occassionally you check to see who this brilliant person or this misinformed writer is. But keeping it the background gives you the courage to change things.
An alternate (and compelling) point of view suggests that the anonymity of colored icons removes reputation incentives from the system. It's notable, for example, that in Wikipedia status is often established in talk pages, where names are evident. GitHub tracks commits and engages in light gamification to encourage participation. Too much anonymity reduces these incentives.
A number of fedwikihappening participants also note that in a higher education environment, the anonymity may be a non-starter -- there are specific practical reasons why contributions should be foregrounded.