To illustrate this, imagine an alternative universe where violence is impossible. In this universe IP as we know it including copyleft licenses couldn't exist as violence or credible threats of violence by a state (or similar entity) is required for enforcement. I want to get as close to this hypothetical universe as possible by avoiding everything that depends on violence and coercion as far as possible.
Granting the freedom to coerce doesn't reduce coercion.
I'm fundamentally opposed to the idea of forcing people to do what I want and that's the clear purpose of GPL.
Somebody not doing what I want is not coercing me. I'm free to use or not use a binary distributed without it's source code, or I can try to reverse engineer it. Forcing them to do the additional work of sending me the source code would be coercing them, it would be impossible in my hypothetical alternative universe, and it would be wrong in this universe.
These are all things that currently threaten the freedom of users and developers.
Ramblings about impossible alternative universes adds very little.
And severely limits the freedom of end users!
GPLv3 protects around tivoization and proprietarization. Other licenses do not.
The net effect is that end users are unable to benefit from the openness.