Why is dragonfire dive described as a fire based attack?

[Tharian]

Foe Requiem only affects magic attacks. As such it only affects attacks by Arcanists, Thaumaturges, Conjurers, and their advanced classes. This can be shown to be true by the exact text of Foe Requiem as it has been modified recently to reflect what it actually does:

Reduces all enemy magic resistance by 10%. MP is drained while singing. Effect is lost if targets move out of hearing distancce, and ends upon reuse. Cannot be used with other songs.

Enemy Magic Resistance specifically refers to resistance to magic attacks. Dragonfire Dive and Flame Arrow are not Magic Attacks, as such they remain unaffected by this ability.