The difference between a revolutionary leader and a seditionist is completely in the eye of the beholder. Fundamentally, a seditionist is someone whose goals and aspirations you do not share while a revolutionary leader is a person for whom you can feel sympathy and whose goals you generally support.
In the link below, we see sedition defined as the crime of inciting rebellion against the government. It is, therefore, similar to the idea of treason. But this is exactly what revolutionary leaders do. People who lead revolutions, by definition, end up advocating rebellion against their government. The people who led the American Revolution clearly did this. Patrick Henry essentially admitted it when (if reports are accurate) he said “if this be treason, make the most of it” in his “Give Me Liberty or Give Me Death” speech. He realized that what he was saying was, essentially treasonous, but he did not really care.
Today, we see the leaders of the American Revolution as commendable revolutionary leaders. But that is because we support what they did. If we disagreed with their motives and goals, we would call them seditionists and traitors.