A violation of Net Neutrality is when an Internet Service Provider (ISP) serves some content slower than others. In other words, a violation is when an ISP gives priority to certain traffic. If an ISP slows down only your Netflix speeds, or prioritizes your Google Search results, that is a violation. Simply slowing all traffic across the board is not.
Don't get me wrong. I'm not super stoked about the throttling issue. It's a bait and switch. But, I understand why they (might) have to do it. Infrastructure can only support so much traffic, and as mobile tech gets better, the systems in place strain under the load. I experience this every day, when in dense areas, I've got full signal, but no data is coming through. It might be the case, that AT&T has to take measures against huge data usage, and break it's promise of unlimited data to grandfathered customers in order to preserve the experience for the group as a whole.
Or, they might just be manufacturing artifical constraints to move people off the plan...
Regardless, I don't want to see the Net Neutrality card pulled in this fight. Net Neutrality is an important concept, but is hard to understand. Misleading the public into further confusion about what exactly it is will hinder progress in that separate (and more important) issue.