And why is that? It takes all shot actions into account.
Are you saying that shot actions don't matter for defensemen? That's what they literally are there to prevent. It's a far more accurate measure than the actual amount of goals allowed, especially for small sample sizes.
If you don't like comparing %s, you can note that in 5v5, Ristolainen has almost 1 whole xGA less than Dahlin(which means that Dahlin's xGA is about 50% higher than Ristolainen's). They have almost the same 5v5 ice time. There we remove the offensive portion.
I still don't understand the stance that stats don't matter for small sample sizes. That's the most accurate measure you have of what happened in those games. Is it valuable for evaluating what might happen in the future? Probably not. But it still tells what happened in those games. And shows that Dahlin's defending hasn't been good by any measure. ¨
...Outside of the eye tests of Sabres fans, I guess. The most accurate stat of all, I know.