Even counting calories, as laborious as it is, has its limits. Weight loss takes a long time for an obese person. A diet has to be also healthy and possible to follow long term.

Personally I have been through 6 different kinds of diet, calorie counting or not. The only thing to put in a dent long term was a very low carb high protein ketogenic diet (but it broke liver enzymes and cholesterol long term, took it 2 years. Exactly at the point where I achieved the right weight too. Yes, it was nutritionally verified.) and a hardcore CR diet which was terrible to adhere to. (essentially hungry all time after two weeks, preoccupied with food enough to be distracting at work. Also nutritionally verified.)

And in our culture you get to tell everyone you will not partake in their food which is extra torture on top.

So yes, the advice is garbage, does not work in general long term in my long and varied personal experience.

Also, obesity is a syndrome. There are many causes and diet is probably very ineffective for most. At best a symptomatic treatment.