“Zulu” is an undoubted classic, although it certainly slanders the name of Private Henry Hook VC: far from being the miscreant shown in the movie, Hook was an exemplary soldier, and I seem to recall reading somewhere that he was a teatotaler.
The battles at Isandhlwana and Rorke’s Drift were victories for the Zulu, but at incredible cost–far more so than their inter-tribal wars in the previous 50 years. And don’t forget the Zulus, in particular under Shaka, were ruthless militaristic expansionists themselves, having conquered, destroyed or driven off a number of other tribes to build their own kingdom.
To return to the OP, I think that bravery as such can exist independent of the larger moral issues, particularly on an individual or small group basis. The 24th Foot at Rorke’s Drift were fighting for their lives, not for the Queen-Empress; the Zulus more to prove themselves in battle as individuals and to gain rich spoils than to rid the homeland of the invader (though the latter was undoubtedly a secondary motivation). Both groups displayed remarkable endurance, courage and stamina; both must have come away with a healthy respect for the other. (One is reminded of the Tenniel cartoon in “Punch” a few weeks after Isandhlwana: a Zulu warrior in full gear is chalking a motto on a blackboard to a chastened John Bull, sitting in a desk. The motto: “Despise not thine enemy.”
Of course, the Zulu attack on Rorke’s Drift was against Cetshwayo’s orders: he had told his brother Dabulamanzi (who was the leader of the impi of three regiments that had been on the sidelines at Isandhlwana, frustrated at not being able to “wash their spears” and partake of the booty) not to invade Natal (the Mission Station was on the Natal side of the Buffalo River, which formed the border beteen Natal and Zululand). Furthermore, he had warned all his impi leaders not to attack the redcoats when they were in a prepared defensive position–which Rorke’s Drift, although makeshift, was.
The little Welsh town of Brecon hosts the Regimental Museum of the South Wales Borderers, the successor to the 24th Foot, and it is crammed with artifacts of the Zulu War, including a chair from the hospital at Rorke’s Drift, Cetshwayo’s head-dress, broken ammunition boxes from Isandhlwana, and of course, most of the Victoria Crosses won that morning.