They block encryption they are violating the telecommunication laws. And so they are not a carrier anymore.
If you mean "common carrier" then the truth is that they never where one.
Maybe we should be looking at the origins of the "common carrier" concept, and learn how they apply to the current situation. A number of historians have written on this topic, and the history definitely applies to our modern network.
Part of the explanation of how "common carrier" arose is in the well-known phrase "kill the messenger". Centuries ago, this was a very real problem. It wasn't unusual for a prince (or other powerful personage) to respond to the receipt of a message he didn't like by punishing the poor fellow who delivered it. The carrier services replied to this in about the only way they could: They opened and read the messages, and if they thought the recipient would react by harming their carrier, they would "edit" the message. And when dealing with a recipient who had a bad history, they'd often sell the message's content to the enemies of the sender or receiver.
Eventually the smarter princes figured out that a reliable message service was worth more than the temporary enjoyment they got from torturing or killing the messenger. So some of them got together with the message services, and worked out an agreement: If a sender and receiver had both signed on with a message company, they could send "sealed" messages, which the message carriers would promise to deliver unopened. But this would only apply if the sender and receiver had both promised not to damage the carriers employees or equipment, etc., etc.
This worked out to the advantage of the princes who joined in such agreements, so the practice spread, and became known (in English) by the phrase "common carrier".
It's easy to see how this all might apply to our current topic. The ISPs are "carriers", but not "common carriers". They have a record of opening and reading our communications, and selling the contents to "enemies" like marketers and government agencies. We're now engaged in collecting evidence about this behavior, and publishing it openly. We should make it clear that, as long as the ISPs continue acting in such perfidious ways, we will continue to work to expose their behavior to the general public, including people they views as their enemies (or "competitors";-).
The parallels to the original situation aren't exact, but we might benefit by knowing the history and trying to find a similar solution that can work today.