No sugar added usually just means it’s full of sugar originally found in the product. A “no sugar added” apple juice will still have an insanely unhealthy amount of sugar.
I don’t know why you think it should mean no sweeteners. (most) sweeteners are categorically not sugar. If you want something not sweet, the label you’re looking for is “unsweetened”.
Besides, sugar is much worse for you than any artificial sweetener.