If this was the case then pretty much everything that utilized linux (including binary delivered distributions) would be in violation themselves.
There is a very important term in copyright law called 'derivative work'. It's a legal term that is designed to define what happens when you create a new work by taking a old work and adding to it. It's defined by the law and case precedent, not licenses like the GPL.
The GPL basically says that if you distribute derivative work under the GPL license then you are required to make the source code available under the terms of the GPL.
Take, for example, the Nvidia kernel drivers. The Nvidia drivers were not original written for Linux. They are more then likely Windows driver code with some compatibility added to make it work with Linux. So therefore they are probably not derivative work and thus are not covered by the GPL. No matter how much the Linux developers or GNU or whoever does not like it they are not the ultimate authority here.
But if you compile the drivers then that act causes portions of Linux code to be sucked into the actual resulting binaries. If that is true then binaries can violate the license.
The #2 most important thing to remember is that law is NOT software. That is it's not like code that you write and then that is what sets up the rules. You can read all the case law and understand the license and read USA copyright code... but that is not enough. You cannot take the law literally. It must be interpreted.
That is one Judge may say that Nvidia binaries are derivative and violate the GPL... and another Judge may say that it does not. And BOTH can be right and their decisions can both be 100% legal and correct.
This is how the law works.
The #3 important thing with the GPL is that it places no restrictions on usage. ONLY distribution. You can combine GPL'd code with all the closed source code you want and use it and it all is 100% legal.. because the license allows this. You have no requirements for sharing code or anything like that. The restrictions only kick in when you want to distribute the software.
So in this specific case the ZFS driver code is a derivative of the Solaris kernel code and is licensed under the CDDL. Just because you make it compatible with Linux does not make it derivative of Linux. You actually have to use Linux code to make it derivative. If they don't do that then it's 100% legal to distribute.
Once you compile it then it'll suck in portions of the Linux kernel code and that is when you _CAN_ run into problems.
It is absolutely true that some binary drivers can violate copyright, but others may not. It depends on the details.