The article is junk because it doesn't get into how it depends on intensity level, what exercises you do, and what you eat.
It seems to me that an hour of exercise 5 days a week is the only way for a person -needing- to lose weight, unwilling to change their diet, and unwilling to engage in intense exercise (defined as exercise that makes you genuinely uncomfortable with probably soreness here and there).
So for your average person, he's probably right. But anybody could have came to the same determination by calculating calories lost in one hour of faster than a crawl walking - intake of calories in a diet. No expertise necessary.
For people who hate exercise and watching what they eat there's two good things and one bad thing. The good thing is that they dont have to be too concerned about what they eat, and they don't have to engage in exercise that makes them uncomfortable (thus more likely to quit). The bad thing is that it demands they take an hour a day to exercise and a lot of people will just give up.
BTW. This is what I tell people who want to lose weight but aren't interested in exercising too much or changing what they eat.
Rule of 1 for eating:
Reduce what you consume by 1. Which means, one less beer, soda, candy bar, slice of cake, etc. If you screw up don't feel guilty (very important as guilt leads to depression which leads to quitting). Its not hard, easy to follow. Cheating will occur but overall a person will say no one more time than before.
Do some pushups until you stop caring to. Go outside and sprint a little till you are winded.
If you have a yard, mow it. If you play golf, play faster. Take the easiest parking spot, not looking for the closest.
If you have a kid, you have no excuse. Go spend time with him/her doing things he/she enjoys. Play soccer, shoot baskets, go for a swim etc.