All sweet treats that use process sugar would be considered bad or unhealthy. So, chocolate milk is no different than the other desserts and candies that are made with white sugar. If a dessert is made using natural sweeteners, then this food may be considered healthier. Chocolate milk is bad because of all of the sugar in it.
The more chocolate syrup you put into the milk, the unhealthier it becomes. One little cup of chocolate milk contains over half of the carbs you need for the day. Also, a glass of chocolate milk would contain more than two cups. When you ingest sugar, it makes you feel slower and it takes longer to digest. Sugar sometimes counteracts the good things you have already put into your body.