Calories in/calories out is not a crock. The problem is people are either not tracking their calories closely, or they are over/underestimating their expenditure.

Read the fine print on that site:

"This calculator is meant to be an estimate only. Actual calories needed to maintain weight may vary based on muscle mass, activity and a variety of other factors such as illness, pregnancy, etc. If you are obese, your actual caloric needs may be less accurate."

The only way to know how many calories YOU need to maintain is to track your own weight, calories, and activity over time. This calculator actually underestimates my maintenance, which is around 2600--it tells me 2200.