More importantly, we don't tie GA or any other usage analytics to individual users. We basically just use it to see where the extension is used and where people are blacklisting sites. We use this data to make the extension run better on more sites. We don't monetize user data in any way. You're right that we should make this point more salient. In our Privacy Policy, we do describe how to opt out by blocking GA, but we should put this somewhere more prominent.
Thanks for the feedback!