I think you may be a little confused between the policy's governing FFDO'S that are working crewmembers and those wishing to ride jumpseat 'airbubba'
As Captain, I decide who rides on the jumpseat at my airline, it is my decision (provided the individual is verified in the Cass system and has the proper documentation) to allow, or not allow them to exercise this privilege, not a right assumed by them, no matter who they are, with the possible exception of an FAA inspector.
Whether they are an FFDO or not is immaterial, I do not have to give a reason to deny anyone a jumpseat in my cockpit, and this is supported by our management.
If your airline denys you this basic authority, I sympathise.
If my FO is an FFDO that is something I have to live with for now, fortunately not often as I mostly fly international where calmer heads have prevailed.
Whether someone is a working crewmember or jumpseater, however I advise them to 'cool it' with the gunplay.(No turning in your seat, posturing 'ready to draw' scaring the flight attendant when she brings me my tea !