Hello Abhay! That's a very good question.
Oftentimes, writers like to play with the multiple meanings of certain words. In this case, "pride" not only refers to the importance the residents give to keeping their reputation but also the pride of haughtiness or arrogance. In other words, could it be that the residents are so full of themselves that they couldn't care less about what strangers think of them?
For your evidence, consider how Twain presents different variations of the residents' pride. Take inspiration from the word's different definitions and other meanings that may not be in the dictionary. Happy reading!