I agree with you about blaming carbs for all our problems is silly. I'm 36 years old, spent my late teens and all of my twenties eating whatever the fuck I wanted, and was skinny the whole time. I have great genetics when it comes to diet, apparently. Constant diet experimentation, though, has shown me that I function best on keto/low-carb diets. I feel better, I think better, I'm regular, I have no weight issues, and I'm not hungry most of the time. All of that is effortless. Carb loading fucks me up, though. Clearly, though, a large and growing number of people who do not have that same luxury (through some combination of diet and genetics) and also are increasingly dying from weight-related issues are looking for ways to not just lose weight but get healthier overall and the science of the day all points to cutting excess sugar and carbs to do it.
I disagree with you about keto diets being flawed. Most of them focus on eating vegetables as much as possible, they just steer you to ones that are colorful and not carb heavy. Also, I don't see anyone making the point that eating only sugar at a caloric deficit will make you obese. It will fuck you up royally, though. The problem isn't just the sugar and carbs themselves, though I'd argue that most of the research shows your body doesn't process them in a healthy way, but the general impossibility of eating a diet consisting of mainly those things while remaining at a caloric deficit. If you can do that, more power to you. Most people can't, and the obesity epidemic proves it.
Did you watch that video? My favorite slide in it is the one with the anti-obesity diet from the 1950's. It says you can eat as much of you want of all green vegetables and all fruits except bananas and grapes. I tend to agree with the idea that sugar is our biggest problem, but mainly added sugars, processed sugars, and refined carbs. Having fruit in your diet isn't going to make you obese, but added sugar certainly will.
