The dissent channel is just a way for FSOs to express there disagreement with US policy. If someone finds that they can not support it as part of their official duties, then they should resign or be fired.
Having spent 28 years at State as an FSO, I don't view this as any big deal. The MSM will hype it, but the actual impact on US policy as directed by the President, will be nil.
The ship of state has only ONE Captain, the President and CIC. If you go on board you are a subordinate sailor and you better damn well follow the commands of your superior.