First of all, they are not the same. State of Jefferson 51st state movement does not seek to become a new country. The Calexit movement is a movement all to itself that would like to have California secede from the United States. The State of Jefferson movement trace’s it root back prior to World War II at its’s peak in 1941.
Even though State of Jefferson pushes to be the 51st state, in 1941 they were pushing to be the 49th state. Alaska and Hawaii beat them to the 49th and 50th states in 1959.
State of Jefferson is a conglomerate of counties in Southern Oregon and Northern California. Since 1941, it has partially lost its sway in Southern Oregon and is still an active movement in Northern California were it often still makes the ballot box and is even favored in some counties.
All in all their message is usually very libertarian and geared towards decentralized government which causes it to loss sway with more progressive counties and urban areas. One of their core beliefs is to give federal land back to states, so the movement is similar to other western liberty movements. Realistically, if they became their own state they would be subject to federal over site that many other states have in the West, but they would be free to form their own local regulations and local/state tax codes without California.
Within the State of Jefferson movement there is a local identity and feeling that is unique to the people that live there. There feeling carries over to the nostalgia that they already voted on it and it has been decided locally but they get over ruled by the super majority of California. This state concept is not to be confused with the New California concept that was overruled. New California is a conservative concept to divide California in two states that better represented by a liberal and conservative majority. It lacks the tradition and history of State of Jefferson.