The details are important yes, but really the only people that noticed it are the people that are anal about it. I've played lot's of military shooters and the like and it never dawned on me that the ranks were messed up on the uniforms. It's just not something I paid much attention to simply because it's a sci fi world, and I don't know what the uniforms of ranked officials are supposed to look like.
If I was playing Call of Duty and I saw a 2 star General with 6 stars or something ridiculous, then I would notice. But it's Mass Effect and I've played it tons of times, never registered to me that the ranks could be wrong. Therefore, not really that important in the grand scheme of things. So the OP being the 1% that noticed, was overlooked.