The purpose of hockey is not to put up the best possession statistics. Sometimes it seems like that's lost -- like players and teams are judged on a game of "keep away" as opposed to wins, losses, and the scoreboard.
These possession stats also struggle to factor in deployment differences, such as quality of competition faced, zone starts, and the quality of chances a player creates and concedes due to good plays and mistakes.
Fans frequently compare players' possession stats in a vacuum, as if everything about their usage is equal, when it is not. Doing so ignores how much deployment impacts statistics, and also overemphasizes the importance of possession metrics.
In many cases, fans are making huge deals out of what amounts to merely a couple of shots for/against over a 100 shot span, and ignoring shot quality and deployment differences in the process.
To further illustrate what I believe is the tendency of many fans to place too much emphasis on possession stats (while also ignoring too much context):
The 1st, 3rd, 4th, and 6th teams in the NHL in CF% missed the playoffs.
The Capitals, who won the Cup, were 9th in the playoffs in CF% at 48.83%.
Now, I'm not saying possession metrics are useless, but I do believe they are too often cited as the definitive authority on player and team evaluation. They aren't.