I'm not sure if this is still the case, but for a while Microsoft would provide source-code to the Windows NT kernel to universities and academic institutions; the source was open (for some definition of "open") but because Microsoft did not allow redistribution and modification, and only allowed the code to be used for educational purposes, it was not Free software.
If A GPL'd the software then C has a right to the exact code running on their device. This is not the case under other licenses that people like to call "more free".
What right is missing: The ability to compile a new kernel for an embedded device. Qualcomm, Marvell, Broadcom, ARM, NVIDIA, and many others. They provide binary device drivers that work only with specific versions of the Linux kernel. Consequently, my home router has more computing power than my desktop 20 years ago, but my desktop was free to run any software and my router is just a router.
Also, Android devices almost never update, for the same reason.
You just aren't free change the terms under which you distribute.
> "freedom for end users but not free to modify and distribute"
That would be: "freedom for end users, freedom to modify and distribute - but not freedom to change terms under which (re)distribution happens".
Which I think is pretty much what they are already saying?
Just read it. If you want total abolition of copyright and proprietary software, fine. If you think proprietary software is ok, you are a total hypocrite to criticize copyleft. Period.
That is, when you acquire a product (for free, or for a fee) -- it seeks to make sure that you can do use that product as you wish. And that if you re-sell it, or share it, those same rights are available for the next user down the line.
The GPL achieves this by bending copyright into copyleft. It is not concerned with allowing people to make money repackaging a piece of software and locking it down in various ways.
So, it is all about freedoms, just maybe not the freedoms that some developers thinks it is/should be about.