It was over a season ago at this point, but I remember seeing some counting stats on stick checks by defensemen for breaking up plays (I think it was Sportlogiq). He was atop that list then, so I imagine he's still up there this season. So his defensive game definitely has strong points that are measurable, just that it's unlikely any one is going to weigh defensive play in any way with something that isn't more visceral.
It's easy to judge offensive stats, but you have to watch with a discerning eye to measure defensive play or know the deepest corners of the internet where defensive stats are recorded and never publicized. This is just a count of times it happens too. We don't even know how to weigh the value of a stick check breaking up a play vs playing the body. Guys might be equally effective, yet one knocks the puck off with finesse while the other uses force. How do you know who is better defensively? Do you count it as a defensive play when the offensive chooses to dump it in ahead of the play because he knew he wasn't getting past the guy? I doubt that's measured by any one but the most behind-the-scenes team analysts, so to assume the award voters ever consider such things is balderdash.
Furthermore, with what we know they consider, he's getting unfairly penalized by teammates who can't convert rebounds he creates or put up screens well enough to amplify his shots. I'm sure a number of those other "top" candidates are racking up points by just starting plays that other players who are more capable can finish.
The silver-lining to this might be that without the media fanfare, our better players can be kept for less dollars when it comes to contract negotiations. I know Chychrun is signed to a longer deal already, but in the case of others, management can point to how they don't have votes for such and such awards and try and keep dollar amounts down due to that. Fox may be great in NY, but by getting hyped up the wazoo, his contract cost is only going to go up, making it better for the player's take home, but possibly worse overall for the team in the future when they have less cap to spend when they reach competitor tier because of the media's narrative pushing.