In Genesis 19, Lot defends the angels who came under his roof against the demands of the local men who want a chance to sodomize the three visitors. From the Torah's description, and Rashi's take on it, it would appear that this was a common practice by Sodomites against new-comers. My question is, wouldn't they have also sodomized Lot when he was a new-comer?
Lot surveyed the whole land and chose Sodom. (Gen 13) He presumably wouldn't have done so if they had such a reputation, let alone stayed if he was actually subject to such treatment.
MORE importantly - Lot arrived in Sodom at a time when he was extremely wealthy (Gen 13). Its very possible that the angels were targeted because they were seen as particularly vulnerable / poor. They arrive in Sodom expecting to sleep in the streets (!, 19:2) and presumably, they looked the part.
I believe this fact - the sleeping in the streets - is a critical element to the story. Its not that Sodomites had a fear of strangers, its that they had a love for taking advantage of the defenseless.