My kids have grown up going on
DCL, and have experienced many pool closings. In fact one day on our transatlantic cruise, my son cut his foot on the grate at the bottom of the Mickey Pool and started to bleed....so bingo, the pool was shut down and cleaned/disinfected. So I felt bad for everyone else, but as a parent I was very thankful that Disney takes these things serious. Even though my child didn't have any diseases or anything, they have to take the necessary precautions.
I have also been on the other side where I caught my son drinking water from the water spouts at the Mickey Pool, and guess who ended up in the medical facility with IV's and secluded to our stateroom due to non-stop throwing up and bathroom problems....my son and me/husband. So we missed 4 of 7 days of our trip (couldn't even go to the shows/dinners/activities) because we were stuck in our stateroom....and we didn't get any reimbursements/discounts/compensation.
Again, Disney doesn't want a ship full of sick people....so I am thankful for their over-protection. I mean do you think the cast members "LOVE" to have to always drain and clean the pools....I would bet not.
PLEASE, PLEASE do not allow this one trip experience to influence your decision to take future trips. Unfortunately we can't control other people and how they "behave" but we can control how we react and how it effects us....I am sure there were other AH HA moments on your trip, try and focus on those and remember those memories.