Except it isn't. Charles literally wasn't champion.
I agree that unofficially Charles was the champion. The stripping was nonsense once the UFC acknowledged that there indeed might've been something wrong with their weigh in procedures that led to him being overweight and not that he'd just flat out missed weight. Once they did that Charles/Justin should've just been a non-title bout for Charles where he's ineligible to successfully defend but Justin can win the belt, or a non-title bout on both parts.
But officially he wasn't the champion as they had stripped him back then. So yes, they did fight each other for a vacant belt, not Charles was defending against him and Islam won it off a defending champion. Charles was not champion when Islam beat him, that's a fact.
DC's point is retarded hypocrisy to hype a team mate but downplay someone he hates by pointing out Jones only won a vacant belt when Islam also did that.