Carbohydrates can add to belly fat, you're right. I think that genetics plays a major role in it too though. Northeast Asians eat a lot of rice, and they tend not to have a lot of belly fat. Exercise and lifestyle may also be a factor as well. I workout, and I need my carbs for energy. I've been doing alright, but I might try reducing carbs to see if I can get a good six-pack going.
Cutting carbs is a great way of losing 'belly fat' but there are many other contributing factors. The stress hormone cortisol, if produced in abundance, can cause belly fat. Healthy eating, training and a healthy lifestyle should all be part of any weight management plan.