That's not a capped plan. A capped plan charges you more if you exceed a specific bandwidth threshold - no matter what you spend the bits on. As long as Netflix, Comcast PPV, Youtube and my private cat videos get charged the same price - I'm fine with that.
The issue you're pointing out is the lack of net neutrality - but that is orthogonal to the pricing.
There is an argument there, in that it costs more real money to deliver video bits the a la carte Netflix way than the cableco broadcast way, but I believe the conflict of interest remains an issue, and the prices I see for exceeding these rather small caps don't strike me as fair.
(Albeit AT&T's, the only choice I have aside from a not so reliable WISP, are particularly ridiculous: 150 GiB/month including I'm not sure what overhead for a continually rising price 2nd from the bottom "up to" 1.5 Mbs down/300+ Kbs up line that currently costs $36/month, each additional 50 GiB costs $10. We'd get a faster line so my father could watch video, at $5/month extra each increment, if the cap wasn't so low and the overages so high.).