Except that you were never promised to get 100% of the available bandwidth. You were promised to get as much data USAGE (bytes) as you want. They may be throttling the avaiable BW if you're an abuser, and you may not like it, but rate was never a part of your "unlimited" plan.
Most of you don't even understand what you are arguing.
You and Miles can keep trying, but as I've already quoted from AT&T's own Customer Agreement, I know what I'm arguing. Show me something that says that only the data amount is unlimited, and not the data over time.
Here's another nugget from the Customer Agreement: "Actual network speeds depend upon device characteristics, network, network availability and coverage levels, tasks, file characteristics, applications and other factors. Performance may be impacted by transmission limitations, terrain, in-building/in-vehicle use and capacity constraints."
Nowhere there does it mention any limitations based on their whim, or that they will impose additional limitations.
Show me that you know what you're arguing.