I dunno 'bout the pods or decor or anything, but since they were built using broadly similar resources (IE, insanely advanced tech) for very similar purposes and fairly similar operational constraints re: acoustics, procedure, etc, it'd be more surprising if they didn't look a bit alike - and a bit like any given senate chamber in any given capital or even any given large theatre or concert hall.

Sort of like how anything that swims using fins is ultimately going to end up looking a bit like a fish - the same needs will produce roughly the same design.