I think people here has so many different believes and diet styles that you will hardly find a conclusion. But from my experience, Yes yogurt is a strong source of calories, plus the milk contains galactose that also turns into additional sugar that will be running on your bloodstream and end up in reserves. Also fat.
Plain fat free Greek yogurt is amazing, lots of protein, I use it to substitute something I would want to add butter or cheese to, it tastes like sour cream. I love it. Plus you can use it to make salad dressing and sauces and all kindsa stuff.