Probably because Viacom does not care. This is most likely a gambit to pressure Google into settling than Viacom actually wanting this data, and actually doing something with this data.
Where the real failure came in was Google not providing a viable argument to protect the data, as compared to how strenuously the company moved to protect its source code.
Slashdot Mirror
"It doesn't say why Viacom needs user names.."
Probably because Viacom does not care. This is most likely a gambit to pressure Google into settling than Viacom actually wanting this data, and actually doing something with this data.
Where the real failure came in was Google not providing a viable argument to protect the data, as compared to how strenuously the company moved to protect its source code.