The Wikipedia has this to say about Siege Mentality:
Siege mentality is a shared feeling of victimization and defensiveness. It is a state of mind whereby one believes that one is being constantly attacked, oppressed, or isolated and makes one frightened of surrounding people. This can cause a state of being overly fearful leading to a defensive attitude.
Although the term evolved from real sieges, today it may refer to persecution feelings by anyone in a group that views itself as a threatened minority. This can be used in the field of sports, where coaches or managers often create a siege mentality in their players by highlighting an environment of hostility from outside the club (whether the hostility is real or exaggerated does not matter). Siege mentalities are particularly common in business, the result of competition or downsizing. Some religious groups may have this paradigm, particularly if they are not traditional mainstream groups.
Within the LDS Church, my witnessing of siege mentality seems most evident in strident apologists and message board moderators. Have you noticed that too? It is especially evident when defensiveness turns to offensiveness with a constant cry of victimization blended in as well. The vast majority of people in my ward are not like this, probably because they are not glued to message boards like you and I.
To those experiencing siege mentality, all of their responses must seem the most logical and rational thing to do, since it is the best way of dealing with critics. After all, haven't they heard this same thing over and over again from the same group of persecutors? Why shouldn't they act this way? After all, it is their Church that is under fire and it is their board and besides, their posters want it that way because they are constantly being victimized all over the place? Why won't it let up? Why won't it stop? The voices pounding incessantly, yearning to lash out and take revenge! Moderators, do your duty!!!
How do we break out of that siege mentality?