But .. a calorie is not a calorie is not a calorie.
For those who eat low carb a fat gram doesn't necessarily give us 9 calories. About two of those calories are used up switching it over to fuel we can use. So while, yes, if you eat way more than you expend You might gain or at least not lose but (for most people) that is a lot easier to do eating low-fat/high-carb as opposed to higher fat/low-carb.

People in general *should* be making more healthful choices than a constant diet of low-carb "frankenfoods", i just don't happen to agree with the "so-called experts'" idea of healthful.