Gowron was corrupted long before he had power. He was a politician. He was only a good guy in TNG because he was the lesser of two evils and had more common interests with Picard and Worf.
It's true the other cultures we see in Trek are no worse than the Klingons in terms of hypocrisy. But in season 7 of DS9, Gowron was taking it to an extreme, putting his desire to take personal credit for winning the war over actually winning the war.
Though the corruption we see in Starfleet is less universal than the corruption in Klingon politics.
it is? Even in Kirk's day, top brass in Starfleet were complicit with outside forces. Even the late Brock Peters/Joe Sisko lol.
Federation corruptness is usually portrayed as being confined to individuals, whereas the corruption of the Klingon high council was systemic.