What was Antonio like before coming to the island in "The Tempest"?
The only evidence of Antonio's nature before coming to the island is in his words on the ship, just before he lands on the island. Any other details of Antonio come from Prospero's descriptions, details colored by Prospero's years of resentment. As you know from being in high school, what person x says about person y reveals the character of person x, not to that of person y. So again, the play gives no evidence of Antonio's nature previous to Antonio's appearance on the boat in I.i.
Antonio and whoever wrote the tempest is gay and retarded because he doesn't know how to speak English.