The War was Fought for Menelaus "Metaphorically" in the Epic
In the epic, the Trojan war is most definetely seen as being fought for the insurrection against the pride and wife of mighty Menelaus. However, if these events are based on a historical event, which we believe it was and as enthusiasts for this time period and history we do hope that it was based on history, then the "Trojan War" was most likely fought not just because of one of the king's being robbed of something, but more because and perhaps only because of the fact that the Argives and seafaring men and warriors of this time were mainly interested in plunder and can greatly be likened to ancient "pirates".
An example of this can be seen in the Odyssey when Odysseus tells of his journies home and as soon as leaving Troy after ten belaboured years, he makes an early stop off at a near-by island where he and his men take the time to stop, burn down the villages, and plunder all the treasure and steal the women.