This is a poor analogy, because the fact the importance of calories in weight gain is far less obvious than the importance of people in a room's getting crowded

I agree with this. There is an idea out there that there are people who eat little but become and/or stay fat; and that there are people who eat a lot but stay thin. This is vaguely asserted to be related to peoples' "metabolism." For the most part, this is not so. When such people are scientifically tested, it almost invariably turns out that their perceptions of how much they eat are simply wrong.

By contrast, nobody seriously believes that some rooms are crowded because people appear from out of nowhere.

As with a lot of debates, the actual debate stems in large part from ambiguity over what exactly is being debated.

those involved in obesity research did not fail to grasp the factors that drive hunger and sedentary behavior,

Well that seems to be the crux of the dispute, to the extent that there is a dispute. According to you, there is no mainstream consensus position on what causes some peoples' natural drives to consume too much food. According to Taubes, it's carbohydrates which causes such drives.