The thing is that the relative humidity was high during that cold snap too. No reason for you to feel like an idiot at all. The only way I have found to drop the indoor humidity lower then the relative humidity would be an expensive dehumidifier. Then one would have to sacrifice the ventilation.
I don't think you did anything wrong at all. These things happen to all of us at some point.
I have been lucky and only had one get it. She lost the tips and her status but made it through.
Touching the damaged tips can make it worse. Keep an eye for infection and excessive bleeding. I read about using corn starch to stop bleeding. I keep a powder on hand made to stop bleeding it is called stipic powder. Probably spelled that wrong. Petsmart or Petco may sell it but the cornstarch is said to work just as well.
The 4 younger ones that hatched in the spring never got integrated with my main flock because the peahens wouldn't let them. It was the funniest thing. So, they have their own coop/pen now that is just right for 4 chickens in that cold snap. Unfortunately for all my boys, I had been moving Memnoch & Mercury into their coop at night because Memnoch & Odyessus still don't like each other even though they don't have hens to fight over anymore. Just the 2 extra birds in there created way too much humidity in the coop for that cold snap. Not putting them in there seems to have fixed that issue.
I figured trying to mess with them too much would make it worse. I did slather them all up the following day to try to keep it from getting worse, but I wasn't too keen on trying to touch it yesterday with the way it looked. He's not bleeding excessively, so I was hoping a wait & watch approach would be okay. Don't want to give him more grief than he already has!
I think my dad might have some kind of stop bleeding powder from when we had hunting dogs, Blue something or other. I'll have to look for that & get some non aspirin neosporin to try to keep the chance of infection down. Thank you very much for your tips! This was def my year to have everything go wrong! LOL