Ramadan: Why were the people of Lot destroyed?

I have a book which tells you the stories of the prophets (PBT) and it says this is one of the main reasons why he was sent to them. If people really believed and feared Allah they wouldnt commit these sins. I agree with what perfume said. Its also true that Lot was sent to the people because of their disbelief in God but the real message and lesson is becuase of the homosexuality of the people.