Considering that I've watched a new automated deployment process nuke an entire network due to a mistake in the config... Sometimes slow and plodding and potentially losing a node (as opposed to 100 nodes) is seen as preferable to the PTBs.

Of course intelligent, incremental deployment works too, but let's not confuse those poor suits...

What about SSHing into each machine not manually, but automatically with OKing all the changes before reloading the configuration?

SSH is great at least in the sense that it's configuration-format-agnostic, mostly-OS-agnostic, client-side-automation-agnostic, and many other things like that.

Is that job security?

They can't fire that person. He's the only one who knows the state of the servers.