I'm not even going to bother with the Dr. Pepper 10 "is just for men" trope. It's a cynical and insulting PR move, and let's leave it at that.
But The Consumerist (bless their hearts) have found a much more original reason to hate the brand:
That's right — the brand is based on 10 calories per serving. But with a serving set at 8 fluid ounces (~237 ml), that would give a 20 ounce bottle something like 25 calories by Consumerist's math. The package, however, rounds down. Considerably.
But what do I know. Me man. Me no do math.