You can lean on the almost entirely made up "officially listed height/weight" of players all you want. You can jump up and down and rave about all 5'10" of Conor Garland while you're at it.
The reality that matters, is that Hughes
is visibly very small on the ice, and he plays to that small size. It's an issue. It limits his upside, and the areas of the game that he is able to effectively have a positive impact.
You can stick your head in the sand and pretend it's not a factor, but it's the cold hard reality of what Hughes is as a defenceman. Doesn't mean he's a useless, worthless little runt of a player. But it's a noteworthy limitation on what he can do.
When you watch Makar, he projects himself effectively all over the ice, and his alleged lack of size is never evident. Whether he's that much taller than Hughes standing around the locker room if you get out the measuring tape or not...it really doesn't matter. He plays and projects himself to a much larger size, and doesn't have the same limitations in his game when it comes to engaging physically.