Apache resigns from the Java Community Process executive committee

I don't quite follow your argument. I don't dispute that Oracle is not bound by the GPL: as copyright holders they are free to distribute copies of the software under whatever license they want.

But the copy I received from Oracle was licensed under the GPL, and that says I can modify, redistribute and distribute modified versions. If the code they gave me exercises their patents, then a court is going to rule that Oracle licensed my use of those patents to the extent necessary to exercise my rights under the GPL. That is the implicit patent grant people are talking about.

Note also that if Oracle were to assert that they hadn't given you the patent rights necessary to modify, redistribute and distribute modified versions of OpenJDK, then no one would be able to redistribute the copies of OpenJDK that they received from Oracle (e.g. your favourite Linux distro). Because if they can't pass on those rights, they have no right to distribute the code.

So can you point out where Oracle has explicitly stated that OpenJDK users do not have the patent rights required to exercise their rights under the GPL?