You have absolutely no data on who left, how many people left, what kind of gamer they were, how often they played, or to be honest anything at all about the people who left. All you know is that some people have left. You don't even really have anything more than anecdotal evidence bolstered by the fact MMOs always shed some players shortly after launch.

This is obviously about getting people to look at the changes 2.1 made and, as someone else pointed out, to challenge the ESO beta.