Yes, properly made chocolate can be rich in antioxidants that are great for your heart and immune system. That does not mean you should eat a ton of it, any overeating will be unhealthy no matter what it is. If eaten sensibly, it can certainly be a healthy snack and a treat
Dark chocolates have been proven to be good for a person's overall health. However, most chocolate that people in the United States consume is milk chocolate, and filled with sugar. Sugar is not healthy, and any little bit of good health benefits in the chocolate is completely overshadowed by the sugar.
Like nearly all foods, in the appropriate amounts, chocolate has some benefits, especially dark chocolate. The manner in which it is typically consumed and the quantities downed, there is really nothing healthy about chocolate. It is just another sugary snack upon which we overindulge and then later bemoan for our diabetes and rotten teeth.
Although chocolate can have some positive health effects, the way it is processed diminishes its ability to be considered healthy. The healthy elements are overwhelmed by sugars and additives that make the chocolate an unhealthy and heavily processed snacking choice. While cocao is inherently good for you, nearly all of it is lost in the creation of sweet chocolate to eat.