You can argue that the government shouldn't have the right to compel someone to hand over data or documents.[1] But the fact is that a broad subpoena power, enabling the government to do precisely that, has been part of American law since before there was a United States. So if you think the government shouldn't have this power, the real question is: how do you change this hundreds of years old practice?
[1] You can argue this, but it should be noted that nobody on HN seems to have a problem with the subpoena power when it's say used to subpoena documents from say Enron's accountants.
The difference is, Enron was suspected of committing a crime. Lavabit committed no crime.
If the government subpoenas an individual for their encryption key, because they have reason to suspect the individual for a crime, it is different than to subpoena an innocent, indirect 3rd party. To me, it's like saying "We don't have enough police to handle this crime. So here - you have to take this gun and help us find the criminal. If you refuse, we throw you in jail."
Any service on the Internet could be used by all types of people, for good and bad purposes, just like a hammer can be used to drive nails or kill someone. You don't throw a hammer manufacturer in jail when someone uses a hammer to kill someone. Lavabit is an innocent 3rd party in all of this, regardless of how their computer system was designed.
[1] You can argue this, but it should be noted that nobody on HN seems to have a problem with the subpoena power when it's say used to subpoena documents from say Enron's accountants.