FamilySearch does not usually own the records belonging to a particular indexing project. The owner is allowing FamilySearch to help. In many cases there is an agreement that the project will be restricted to a certain geographic area. Volunteers must live within the area to participate.
If you find that a certain indexing project you would like to join is closed, the reason is likely due to one of these restrictions.
Thank you for your desire to index records. You are making it possible for people around the world to discover their ancestors. Please attempt to join another indexing project.
Related articles
How do I join an indexing group?
What are the upcoming indexing projects?
I can't find any batches that I want to index