The use of sedition during times of war can be permitted, but the circumstances and communications censored by the government have to fit within a very narrow category. As the Supreme Court held in New York Times v. US (the Pentagon Papers Case), only communications dealing with troop movement or other military activity should be censored.
Human biengs have inalienable rights, including rights of free assembly and free speech. When a group of people gets together to promote a change in the status quo they are often branded by the ruling power as criminals who are trying to incite sedition for no other reason than to stop change from happening. In other words, it is better to allow what some might call sedition in times of war so as to guarantee that everyone's rights to free speech are protected rather than to let the government decide who has a right to speak and advocate for change.
I think that even though a lot of us would not agree with it, I still think that sedition during a time of war should be allowed. As long as the people involved in such behavior is not breaking any laws, I don't see anything wrong with it as long as they are lawful
Sometimes people have to stand up and fight for what's right. If the situation is so grim to where people feel they truly need to stand up and rise against the government, then they should and should not be thought of badly if the cause is just. Sedition is terrible, but only if the government isn't worse.
I'm about as libertarian as they come. Realistically speaking however, even the most liberal government is going to intervene if some one is spreading sedition during war time. Assuming that it's a real war, as in something where one's homeland is at stake, as opposed to the fake police actions the US has been involved in for decades of course.