He's kinda right… right?

Not really, Discord created a nice Catch 22 for Dashie where no matter which option she went she'd betray someone. If she stayed in the maze, she betrays Cloudsdale by letting it be destroyed, which is obvious, except she also betrays her own ethics by abandoning the city to it's fate. But by leaving she betrays her friends, her ruler's orders, and more importantly her duty to protect the whole of Equestria in that instance as an Element Bearer. So no matter what she goes through it ends with at least one betrayal, allowing Discord to corrupt her and her element.