Isabelle... They?? Who is "They" It appears that you are referring to three or more possible targets One the specific family that you call neighbor (I suppose because of closeness in geography to you) Two The Church of Jesus Christ of Latter Day Saints (not the members) or Three All members of the Mormon church! To infer that Mormons are Judgmental is like saying you must be Mormon because you live in Utah, everyone knows that all Utahans are Mormons! (Very ignorant to say the least right!)
First, I would start by saying that people are people REGUARDLESS of their religious beliefs. People either choose to act on their beliefs or not! I would be disappointed and feel sorry for the family that would treat you or anyone that way. I would also go so far as to say that it is inappropriate behavior for any Christian, Mormon, (insert label here) to treat anyone like that! Second I would say that it would not take me 1+ years to introduce myself by asking for help to get that response! Also I would not categorize my "neighbors" by religious beliefs, rather I would hope to call them friends and try to find common threads that would serve to foster healthy relations as "neighbors". One such way would be to talk about work, talents, sports, computers, cars, crafts, needlepoint, sewing, cards, games, children, yardwork, service projects (insert hobby/interest here) etc... There are many other ways that do not include sitting at home and counting/labeling who in your neighborhood is good enough for you to associate with based upon perceived religious beliefs. (In fact take religion out of the equation and just focus on being a friend) Finally I would challenge you to go to that "neighbor" and apply the teachings of Jesus Christ by COMPASSIONATELY explaining to him that he has offended you and that you forgive him/them for that! Then I would without hesitation reinforce to him that you want to be his neighbor and would like to get to know his/her family and that you would be that "neighbor" to him as the Savior described. Yes Isabelle, you can be a great influence in their life to help them to be good neighbors through your example!
Ps when Jesus taught about neighbors, it had nothing to do with geography!