then God would have destroyed a million cities on earth already by fire and brimstone.
you're wrong; that can't be right either, by exactly your own reasoning.
they were doing something far, far worse there -- the thing that was being done in Gibeah. something that you can take one look at a corpse and immediately know the entire place must be utterly destroyed, every person and every animal.
you can't tell someone has had homosexual relations by glancing at any twelfth of their corpse.
there's something else going on there.
Actually, I'm surprised that you said that God destroyed those cities because of their neglect for the poor and their idleness, as the information contained in that event is straight forward.
I believe that the scripture that I gave you out of Jude regarding Sodom and Gomorrah supports what I am saying.
The Lord doesn't need to look at anyone to know that they are practicing homosexuality and going after strange flesh. He sent the two angels to Lot's home to get him and his family out, because he was going to destroy them because of men's lust for one another. This is demonstrated by the fact that the men young and old surrounded Lot's house and demanded that he bring out those two men (angels) so that they could have sexual relations with them.
"In like manner, Sodom and Gomorrah and the cities around them,
who indulged in sexual immorality and pursued strange flesh, are on display as an example of those who sustain the punishment of eternal fire."
According Jude, their sin and why they were destroyed is made obvious in the scripture above.
By the way, not everyone was indulging in same-sex life style. So no, the Lord would not destroy everyone else by my own example.
There was only one reason that the Lord destroyed those cities and it is because they were going after strange flesh, men with men and most likely women with women.