Was Ovid's Banishment Justifiable?

Ovid was banished from Rome because of his book "Ars Amortia". He says that is was because of "a poem and a mistake". Augustus was mad about the fact that he had written the book, which included how to carry on affairs, and because that Ovid knew that Augustus daughter, Julia, was a bit a promiscuous type and he didn't tell Augustus, but rather told half of Rome instead. These actions and behavior landed him in the barren frontier town of Tomi. There he was exiled for some odd years starting in 7 A.D. (the same year as Julia was banished) and his banishment continued from then on out. Then Tiberius took over in 14 A.D. and Ovid lost all hope for he had written in opposition of Tiberius and rather in favor of Germanicus. In Tomi he wrote Tristia and continued work on Fasti before his death which occured in 17A.D.
Ovid probably got what he deserved. I don't think it was the mere fact that he wrote a book about how to have affairs and how to carry on other promiscuous activities, but rather the fact that he told everyone about the promiscuous activities of Augustus' daughter, and the fact that he didn't tell Augustus about it first. Another reason his banishment was rightfully continued is because he got involved in politics between Germanicus and Tiberius. You should expect something bad to happen to you if the opposite party wins and you wrote something terrible about them in the beginning. Ovid ultimately got what he deserved and its a shame he just couldn't keep his mouth shut.