Complex sentence: Cleveland claimed to have had the original idea, based on the experiences of his father who was a Korean War veteran, and felt offended that Sorkin had not given him a chance to honor his father's memory at the award ceremony.
Split into simpler sentences: Cleveland claimed to have had the original idea, based on the experiences of his father who was a Korean War veteran. He then felt offended at Sorkin, who had not given him a chance to honor his father's memory at the award ceremony.