I predicated my statement on the basis that the horse has full time access to shelter, water and hay. I lived in the PNW and my horses had the choice to go in the shelter or stay out. Letting a horse get rain rot to that degree is sheer abuse and neglect and putting a blanket on a horse and never checking would have been just as bad. Did the horse also have a raging case of thrush?
I know I tend to be blunt, I will make more of an effort to try and see how my statements come across.