Removing impediments
The Scrum Master is responsible or accountable for removing impediments, or should they take a neutral stance and merely facilitate alternatives for the team to remove these impediments, aiming for self-organization ?
The Scrum Guide says that the Scrum Master coaches team members to self-manage, and causes the removal of impediments. So the more impediment removal is caused by self-management, the better.
The Scrum Master is responsible or accountable for removing impediments, or should they take a neutral stance and merely facilitate alternatives for the team to remove these impediments, aiming for self-organization ?
The question is Can the Scrum master solve the impediment all by himself without the teams help? Probably not.
Like @Ian mentioned SM should coach the team to self-manage and remove impediments. For inter team dependencies/impediments the SM may have facilitate some meetings with the concerned stake holders and help the teams communicate.