Obviously I disagree.
You can read the technical documents (MoU regarding Harmonisation of a Charging Capability for Mobile Phones, google it), look more carefully to the section7.
"The EPS shall short the D+ and D- lines with a resistance not greater
than 200 ohms."
Said this, I also believe that if you buy a proper certified device it is the perfect option, unfortunately I see a lot more product choice for iphone then other brands.
For instance, I first realized about the short when I bought a PowerBolt™ Duo Car Charger from Kensington, I said to myself, great!! 2.1 A and another 1A USB plug, I will be able to charge anything.
But when I first connected it to my phone, it was charging alright!!, but Slow charging, only after some investigation I found why, the PowerBolt didn't had the Data pins linked together, and the phone limited the power drain.