Where did you jump to the assumption that people are using damp/wet towels? We re-use towels, but I have never used a damp towel.
If the towels remained even slightly damp, they would smell mildewy. That's why we hang them up and ensure that the bathroom has proper airflow so it's not humid. Even if we are not going to reuse, I still have to hang my towels to dry completely after each use. To me, tossing wet towels into a hamper to sit for days before washing is gross because there is more time for bacteria and mold to grow while they are sitting damp in the basket.