You're confusing routes with endpoints. CDNs are endpoints--multiple endpoints containing the same data so that there is a much higher probability of having an endpoint close to any given user. The owner of the data has to do all the work of getting multiple copies of the data placed at all those endpoints, making sure they're all in sync, etc. But the data traveling from endpoint to endpoint--from the nearest CDN node to the user--is not privileged over any other data.

What the net neutrality debate is about is the ISPs wanting to control routes--i.e., to be able to say that some data traveling over a given route from one endpoint to another endpoint gets to travel faster than other data traveling over the same route. CDNs don't do that.

What Netflix bought from Comcast is sort of in between. It's like a CDN in that Netflix still has to do the work of placing multiple copies of their content at different endpoints in different locations; but it's also like the ISP route control scheme in that Netflix' data gets a privileged route from their endpoints to Comcast users, a route that non-Netflix data from endpoints that are similarly situated does not get, because non-Netflix data can't travel through the special connection points that Netflix now has with Comcast. Normal CDNs don't do that either.

The transparence on what is being payed for and why some sites are fast and some are slow is not the same for Comcast's subscribes in the two scenarios either.