They're not bad for you, and they provide quick energy when you need to do cardio style workouts or supersets. Just don't eat a loaf of bread each day or drink shitloads of soda. If you are trying to lose weight, it is generally accepted that lowering your carb intake is a good thing. The crazy zero-carb stuff is just that: crazy. The reason why it is generally considered good to lower your carb intake is because a shitload of "empty" calories come from that, usually in the form of sodas and white breads and, well, sugar. Fruit has a -ton- of carbs in it, but it also has a lot of healthy stuff. Things like Soda and white breads are basically carbs and not a whole lot else. So you don't have to go zero carb at all, nor should you as you lose a lot of quick energy options from your diet and it will make any sort of physical activity that much more difficult due to the lack of healthy sugars in your system. But if you are someone who drinks a soda/beer or two each day and you aren't working out to burn past those empty calories, removing those beverages and keeping your white bread intake (I'll add white rice here as well, because it is another "empty" calorie) will make weight loss goals a little easier to hit, at least initially.
The only people who should do zero-carb stuff are the ones who are regularly seeing nutritionists to monitor their health, or are spending a substantial amount on food/supplements to sidestep the easy quick carbohydrates. And even then, I personally think the zero-carb stuff is nonsense. Just don't make half of your daily caloric intake carbs from empty calories and you'll probably be alright as long as you are at a caloric deficit.
