Some portion of people who choose to install a browser extension being traceable is worlds different from the government mandating that ISPs track all internet activity of all U.K. citizens.
But most people don't know what happens to their data, and many don't even know that they're being tracked when the opt in to provide "anonymized usage statistics".
Of course it's a completely different if the government forces total surveillance, but the impact on people's privacy can be just as bad or even worse.
That distinction should be plainly obvious.