Genesis 19:9

The people of the Ancient Church at the time described in this story were in a state of external worship - meaning they had rituals and stated beliefs, which in their minds made them holy, even though their desires, intentions and actions were evil, filled with selfishness. The remnant represented by Lot were pretty much the opposite - despite the teachings of the church, they clung to the idea that being good mattered, that they should care for others and act in a caring way. So while the people of the church felt threatened when the Lord connected with that state of caring and wished to deny Him, they felt all the more threatened by the idea that it was important to be good, and were prepared to attack it with even more violence. And in coming near to break down the door, they threatened to attack that desire for good on an even deeper level, and to attack ideas of the Lord as well.

Again, this also represents part of the process we go through in battling temptation. Like Lot, we try to protect and internalize things that are good while staying on friendly terms with our evil desires - we may not want to internalize them, but we don't quite want to get rid of them either. But when we deny their attack on our trust in the Lord, they will directly attack our desires to be good.

Consider an alcoholic, proud that he's been sober for several months. He's felt doubts about the Lord: What if there's nothing to it? Should he fight so hard to stay sober if this life is all there is? But he's pushed those ideas back. Then more doubts assail him: Who is he to be proud? Look at the damage his weakness has done! How can he hope to be better? Who does he think he is? If those doubts can overcome his desire to stay sober, then they can invade and destroy everything.