I also need to emphasize this. A story can have deep political themes but not be a political manga, you have to assess the root/thesis statement of the manga itself. Series like Kingdom, Code Geass, & Gundam are political manga by its very definition since its thesis involves warfare to establish a political ideology. The root of One Piece is more about freedom and chasing ones dreams... in order to do that, there are obvious political obstacles they have to overcome which come later into the stories. Two things can absolutely be true. One Piece isn't a political manga but its littered with political themes, conflicts and ideological debate (Elbaf). Just my two cents. I'd actually argue that One Piece has lost sight of its roots as it has shifted to a much more political focus lately with deeper focus on the WG, Imu and Joyboy.

Better than Naruto