I thought that too at first. But the NYT op-ed does a better job of explaining.[1]
Basically, they think that the NSA has the ability to index anonymous readers with pages visited, and anonymous editors with pages changed. Then if the NSA is sending that data to a bunch of governments around the word (Egypt, Israel, the Five Eyes, whoever else), dissidents around the world are at risk of being caught for browsing/editing Wikipedia for the crime of being opposed to the government in power.
Basically, they think that the NSA has the ability to index anonymous readers with pages visited, and anonymous editors with pages changed. Then if the NSA is sending that data to a bunch of governments around the word (Egypt, Israel, the Five Eyes, whoever else), dissidents around the world are at risk of being caught for browsing/editing Wikipedia for the crime of being opposed to the government in power.
[1] http://www.nytimes.com/2015/03/10/opinion/stop-spying-on-wik...