I agree with you. The motives of those with access to this information is questionable and being forced to do things impedes personal liberty, but the people who wrote the constitution could have never imagined this type of situation. It quite literally requires an in-depth discussion by the people and those we trust in power to develop a solution, but the idea that no backdoor will ever exists is not realistic.
Look at history. The encryption the Nazis had created helped them commit terrible acts of war and it was the backdoor the Allies discovered that helped bring justice to them.
I'm being devils advocate here because I don't people should view this as "us vs them". Comey may seem like he is salivating to you, but he does raise the notion that at the other end is a corporation, who also has an agenda.