My nitpick about EnemySpaceship: whether an entity is enemy or not should not be part of its type but part of its state and/or logic. I know it's "just an exam

My nitpick about EnemySpaceship: whether an entity is enemy or not should not be part of its type but part of its state and/or logic. I know it's "just an example" but to me this thread is about whether arguably incorrect examples are bad practice or not.