(And it works for some people, much the same as other diets. We know this. And some people are sensitive to carbs, so I am not including them in this AIBU).
But I think most naturally slim/fit people eat carbs. They just don't gorge on them.
Many who go low carb began quite overweight and were probably eating large portions before. Changing their diet and becoming more mindful is likely the reason for weight loss, not the total annihilation of all carbs.
It's all a bit evangelical isn't it?
Plenty cultures enjoy rice, bread and pasta. But I have seen these foods described on MN as.... and I quote.... "nasties'. What utter, utter tripe. There is a huge difference between a serving of wholegrain rice and a sugar festooned donut!
There are healthier carbs than others, like most foods, but it is very easy to locate bread made with only a few ingredients, similarly to what you could make at home. The excuse that all bread is full of sugar and oil is a cop out IMO.
Most people I know who are slim and healthy eat bread or pasta, or both. It isn't the work of satan. It is quite easy to incorporate healthy carbs into one's diet, whether daily or weekly and stay healthy and slim. I wonder if those who claim they can't eat carbs or else they gain a ton of weight immediately are not able to them it in moderation, so it's easier for them to just quit.
For the record I don't favour low fat diets either, I also believe that fat is good for us.
Unless you have a health related issue that requires you to reduce carbs, then I think YABU! 