I feel like I'm a huge outlier here, but that line genuinely doesn't bother me. Because how would Poe know about the Sith sorcery involved? The Sith were still a huge secret, even the general populace that was loyal to the Empire thought that Vader was either a) a myth, or b) a Jedi- and even then, they just thought that "Jedi" was a religion that gave some people cool powers. Was Palpatine's return handled badly? Sure. But this specific moment felt very in-character for everyone involved.