Who actually was Bargh? He's the "leader of the Klingon Oversight Council," who are supposedly tasked with approving the eligibility of officers. That doesn't sound like a body which would actually command ships or fleets directly, but Ma'ah describes his ship as being part of Bargh's fleet. Bargh's death is also not presented as something that would significantly shake the Klingon government. Kor had been on this council (and rejected Martok) in 2345, but Kor would have been approaching 100 at that point and likely wasn't especially active in day-to-day military command.
So is Bargh essentially a minor administrator on a power trip, or a person of significant status and power who commands fleets but also has a role on this relatively minor council? My inclination is the former, and Ma'ah is expressing some sour grapes in referring to "his" fleet, but it's not clear.