“Before they lay down, the men of the city, the men of Sodom, surrounded the house, both young and old, all the people from every quarter;”  Gen. 19:4

The people in the mob are referred to as “young and old”, “from every quarter” and even “small and great” in 19:11.  This suggests a wide demographic of people from the city are involved in the ordeal.  It is possible that it is a crowd that gathered out of curiosity for the spectacle, not unlike a public hanging or similar.  However, this is likely highlighted in scripture to enforce to us that the whole place was wicked, and thus deserving of judgment to soon come.