Says who, You and the others that be spewing the bro science? I give my plants plain water in coco and let them go completely dry with no ill effects, and here you are telling me along with others "don't".
The thing is, just because
you don't run into issues (as far as
we know) doesn't mean it's good advice to a new grower or someone already experiencing problems. Someone new to coco is almost guaranteed to run into issues with too much plain water and/or dried out coco.
I re-use my coco (roots and all) until it's dust but I would never recommend that to a new grower. If I mentioned all the things I do growing in coco half the forum would collectively freak out. Just because
I do something and get away with it, doesn't mean it's good practice.