A jury can invalidate a patent too, but for a judge or a jury to invalidate a patent, the moving party (usually the defendants accused of infringement) must prove by clear and convincing evidence that the patent is invalid.

In a PTO reexamination, the requester/PTO only need substantial evidence to invalidate a patent, the standard of proof is much lower with the PTO.

In this case it appears those patents in question were really "dumb-$$$ patents".