"why not just stop access to port 123 UDP on the machines until fixed"
Or disable the software that listens on that port. But perhaps (one might say "hopefully") there are watchdogs in place to start it again? So stop the watchdogs? Unless it's watchdogs all the way down, I suppose.
Also, under the current administration, I would be keeping quiet about being a "federal employee actually paid to watch the clocks all day", lest the idiots at the top deem the role unnecessary.
Jon