I agree that the level of severity of withdrawal symptoms from hard drugs is quite different and more severe than the symptoms of withdrawal from sugar and/or caffeine, which is why hardcore substance abusers need to detox in a medically supervised facility, but that doesn't mean that someone can't be addicted to sugar or caffeine. The severity of withdrawal is more of an indication of the level of addictiveness (and the physiological effects of a specific drug on the body) of the substance than it is of the level of addiction.
Nobody is trying to minimize the seriousness of drug/alcohol addiction or the experiences that those addicted endure to get off those substances, but rather to make a case that sugar fits the critera as an addictive substance as well, even if the severity of withdrawal is less. Why get into a comparison of "my withdrawal was worse than your withdrawal"? Withdrawal symptoms are withdrawal symptoms and indicate an addiction was/is present.
But for comparisons sake, I've gone through both nicotene withdrawal and carb withdrawal and the symptoms were fairly similar in both cases (headache, anxiety, nausea, extreme cravings) and yet the Surgeon General has compared nicotene addiction to heroin addiction as far as the level of addictiveness of both drugs. I wonder if the Surgeon General was trying to insult recovering heroin addicts with that statement?