Why is the Trojan War called the Trojan War?

Answer 1

Its proper name is the Iliad. In Classical Attic; sometimes it is referred to as the Song of Ilion or Song of Ilium (Ilium and Troas was the archaic and Classical period Greek names that Troy was known by).

The name of the poem, meaning 'of Ilion', is an ellipsis for 'a book on Ilion'. So no one named the poem this way, that was just how the Greeks referred to it (because of its immense popularity, everybody knew which book on Ilion you were talking about). In present form, the name was probably first employed in an extant written text by Herodotus (II, 116 sq.).

The war was sparked by the theft of Helen the wife of Menelaus of Sparta. The main objective contrary to some flawed and biased opinions was to take back Helen and punish the Trojans for their insolence after initial requests for Helen to be returned had been declined.

Sacking cities during the Homeric bronze age archaic time was a method of waging war. It was how they fed their troops and kept up supplies and how the military was 'paid' for their service. 3,000 years ago it was the way things were. These were ancient warrior cultures and can't be judged by modern standards to fit a modern narrative.

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The main objective of the Greek looting expedition in Asia Minor was the richest city - Troy.

Trojan is a the adjective of Troy.