It doesn't seem out of line for most of the leave your life for weeks/months to get a jumpstart on your weightloss/health sort of places.
Yep, a lot of people can make fairly minor changes to lifestyle and get back to a healthy weight, but for a lot of people there is a need for a drastic change of lifestyle, and sometimes that is easier to do at a place like the ranch (which like I said doesn't seem out of line with other in house medically monitored weight loss programs. I live near one of these and they get a fair amount of local coverage as to what they do/how they operate)
If you go back to whatever made you fat once you lose the weight you will gain it all right back. It made you fat once, it will make you fat again, so it is about a life-long change, not a short-term diet. Some people do need the whole get away from my life and learn a whole new set of behaviors in order to get a start on any sort of significant weight loss thing. One of the reasons gastric bypass works so well for some people is that the surgery forces you to change how you eat because if you ate the way that made you fat you get so sick from the food that almost no one will eat that way. Any enjoyment you might have gotten from eating the food is drowned out by being physically ill.
Most of these programs are designed to give you enough of a jump start that the more normal levels of exercise and diet that one can do in the real world isn't so frustrating you give it up. Working at it for a month and losing only a couple of pounds will make anyone who has 100 pounds to lose so frustrated they give up. Losing a significant amount of weight in a month or two like they do on this show often gives people enough hope that they will keep at the amount of exercise and diet that will let them continue to gradually lose the weight.
It's a tribe creation!
I'm on a diet now and gave myself 1.5 years to lose the weight, which is more than a lot of people feel they can do. If I could afford get to a place where I could drop a lot of weight in a month I'd love to do that. Just not in the budget, or work schedule.