I don't know enough about Coolidge to have my opinion be worth much here, and of course it's always fair to argue whether any win or loss during or after a president's term should be attributed to them, their predecessors, or (in the last case) their successors, but there's a lot of ground between "not really responsible for the Depression" and "the greatest president!" I would have been less surprised by the first claim, but it seemed like linguae was making the second.