I don't buy it. I developed diabetes insipidus, a rare chronic disorder resulting from a lack of antidiuretic hormone, sometime in the last five years. Thankfully mine is relatively mild and manageable without any sort of intervention, but my body is basically always in the mode most people are temporarily in when they drink large amounts of diuretics (alcohol and caffeine, for instance).
I pee about 3L of water a day, about three times as much as the average person, because anything I drink goes right through me just like when people are drinking large amounts of booze or coffee.
I wake up in the morning with an intense need to urinate (unless I woke up in the middle of the night, it's about 50/50) and extremely dehydrated, with dark circles under my eyes, even if I drank 32oz of water before I went to bed. If I don't drink water for a couple hours, my vision goes blurry, my mood sours, and I develop dark circles under my eyes. More than that and I become dehydrated. The hormone also controls thirst urges so I'm never not thirsty, only somewhere between thirsty and completely parched at any given time.
This is all to say that I drink substantially more water than the average person. I chug two pints of water before I wake up. I drink about a pint of water every 90 minutes at work and then will drink La Croix and water after work. On an average day, I drink probably 18-20 cups of water, which is more than twice the recommended amount (and most people don't drink the recommended amount).
I find it hard to believe anyone, even if they're sweating constantly, could drink twice that. If they don't have a problem like mine, their body will tell them to knock it off because at a certain point it becomes dangerous. If my condition was worse and I had to take synthetic hormone to manage it, the amount of water I drink would verge on dangerous territory and could lead to hyponatremia because it would overload my kidneys and could cause a stroke.
Drinking water is good. Most people drink too little. But, yeah, that amount is crazy. It's ********.