So much of the discussion is about what he said has any truth. I think this is beside the question. He Wrote and distributed materials criticizing his employer's core HR mission while alienating coworkers.
If you're a person targeted in his manifesto, I'd suspect you'd no longer want to work alongside him. That's reason enough to fire him on the spot. He's creating a hostile work environment via coworkers and media.
For those that doubt it, I say try it at your job and see what comes of it.
Honestly, what did he think would happen?