Yes, according to the FCC, AT&T is violating net neutrality rules with its DirecTV data cap exemption. In this manner, AT&T is favoring DirecTV video over other companies on its mobile network. Favoring one company over another is in violation of neutrality rules. The FCC has investigated this issue and I'm sure they're correct.
AT&T has been slowing down customers data when they try to visit rival sites, despite the fact that this is prohibited by net nuetrality laws. They know that these laws are difficult to enforce because throttling is hard to detect unless someone reports it, and it then requires an investigation.
AT&T have constantly shown their dishonesty and lack of respect for their customers. They will play the game as long as they can, and no one can stop them. The government needs to crackdown on companies like AT&T and protect the internet in the interest of fairness. Bigger sanctions is what is needed, but something tells me it's wishful thinking.
People who own phones are very particular about their service. They want the Internet to work. They want the Internet to work quickly. AT&T is not violating net neutrality rules because they want to provide a service that works well. AT&T wants to get rid of the junk on the Internet and provide service.