Since you're talking DF instead of PF and it doesn't sound like you're on JP, you've answered your own question. Think about what a new person sees in the game. They do this questline and it unlocks this new way to do this trial they did before, and the game says "Go queue up in DF to do this". When they run other DF content for things like dungeons and trials in the story, more often than not they don't encounter anyone expecting them to look at a guide for something they're new to. So why would they think it was required for something else they're new to? I think you see people expecting carries more in PF since they can see the requirements there and ignore them. But you're probably running into mostly new folks who don't know any better than to use the DF for that content since they haven't learned that particular community quirk.

Also, for guides in general, they often don't help a lot of people. Some need to be in there in the moment reacting to really understand things.