The homosexual wickedness of Sodom is clearly illustrated in the Bible;
But before they lay down, the men of the city, [even] the men of Sodom, compassed the house round, both old and young, all the people from every quarter:
5 And they called unto Lot, and said unto him, Where [are] the men which came in to thee this night? bring them out unto us, that we may know them.
6 And Lot went out at the door unto them, and shut the door after him,
7 And said, I pray you, brethren, do not so wickedly.
The "wickedness" of what the men of Sodom were attempting was homosexual in nature. What they were proposing was homosexual rape. For such an event to include virtually "all the men of the city, both young and old"..homosexuality must have been commonly practiced.
There is evidence in other early literature connecting Sodom with more general homosexual practices:
The second-century BC Testament of the Twelve Patriarchs labels the Sodomites "sexually promiscuous"(Test. of Benjamin 9:1)and refers to "Sodom which departed from the order of nature" (Test. of Nephtali 3:4). Both Philo and Josephus plainly name same-sex realtions as the characteristic veiw of Sodom.
Ezekiel also says of the Sodomites "they were haughty and committed abomination before me" and the sexual nature of these "abominations" is suggested in 2Peter 2:6-7; "And turning the cities of Sodom and Gomorrah into ashes, condemned them to destruction...and delivered righteous Lot, who was oppressed by the filthy conduct of the wicked"..
In Jude 7 we similarly read "Like wise Sodom and Gomorrah and the surrounding cities, which in the same manner as they, indulged in sexual immorality and pursued unnatural lust, serve as an example by undergoing punishment"[NRSV].
Note....Jude 1:7 (KJV)
Even as Sodom and Gomorrha, and the cities about them in like manner, giving themselves over to fornication, and going after strange flesh, are set forth for an example, suffering the vengeance of eternal fire. .... indicate that homosexuality is a sub- category of fornication.
That this is the type of fornication being described here.
Certainly the Sodomites were guilty of other sins, besides homosexuality..but with the number of the references being to Sodoms sexual sins,and the indication homosexuality was widely practiced..it is likely this is one of the many reasons judgement fell on them.