I finished this volume on the same day that I started and finished Elie Wiesel's Night. While I've noticed FMA's allusions to Nazi Germany in the anime before, I was hyper aware of them while reading the source material. Human experimentation, genocide, eugenics, and the rise of facism are all highlighted. It's a heartbreaking allegory of human suffering and people's responses to grief.
Yes, FMA is a shounen manga. It's also a critical piece of literature.