Users still have control. You can remove plugins you don't like, and if you really want to, use a version of a plugin which allows unsigned extensions.
You could argue that as long as users can still download a disk editor and change any byte of the disk on their machine they still have control (in fact patching out this signature check could probably be done with a single-byte change to the binary...); the problem is when this control is made more and more difficult.
You could argue that as long as users can still download a disk editor and change any byte of the disk on their machine they still have control (in fact patching out this signature check could probably be done with a single-byte change to the binary...); the problem is when this control is made more and more difficult.