All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu 'alyhi wa sallam, is His slave and Messenger.
First of all, it should be known that Loot (Lot) was like other prophets, may Allaah exalt their mention. They brought Islamic monotheism to their people and called them to worship Allaah The Almighty alone. Allaah The Almighty states this generally in the Quran Saying (what means):
When this fact is fully comprehended, it generally eliminates any misunderstanding. Nevertheless, there is still the question why the Quran does not mention through the words of Loot that he called his people to worship Allaah alone, as it did with the other prophets, May Allaah exalt their mention. The reason for this might be the gravity of their disobedience, for they contradicted human nature as well as the Divine Law and innovated unprecedented sins, the severest thereof was having sex with other men. The Quran explicitly stated that Loot rejected their action. Allaah The Exalted Says (what means): {And [We had sent] Loot when he said to his people, “Do you commit such immorality as no one has preceded you with from among the Worlds? Indeed, you approach men with desire, instead of women. Rather, you are a transgressing people.”} [Quran 7:80-81]
Allaah Knows best.