It seems you've misinterpreted the poster's intentions as if it should be illegal for a developer to do this. But he/she was merely informing users, and well informed customers is a requirement for capitalism to work.

The cost of using this extension is your information, and there are other products available that do the same thing at a lower cost. Based on the most fundamental concept of economics (supply and demand), "The Great Suspender" should fail as a product very quickly.