I saw a guy biking on the trail last night with a bandanna around his face and I thought, "no matter how much it doesn't make sense to be masked in certain situations there will always be people who do it".
Less than a minute later I slammed into a swarm of gnats so thick I heard them ticking off my helmet and had to look down to keep them out of my face.
Moral of the story, I'm not going to judge maskers, they might know something I don't.