Defenses are well crafted, and we all use them every minute of every day. These things tend to work better if they are somewhat unconscious, so when you bring someone’s defenses to their attention, you often get an explosion. This is because the person is reacting to the uncovering of their carefully buried defense.
By exposing it, you have laid his defenses bare, and now they won’t work quite as well. Because defenses work best when somewhat buried, most people deny their defenses and push them back down out of consciousness so they will work better. This is all carefully crafted behavior but hardly anyone realizes that they are doing it or at least they do not want to realize it.
In fact, if you even bring up the subject of psychological defenses (even saying that they exist or discussing them in general with no reference to anyone) to most people, you tend to get a very quick shutdown of the conversation, usually with annoyance, anger or mild ridicule. We don’t even want to know that we have defenses! We think if we know we have them, they won’t work anymore, so we deny that there is such a thing. Actually most people know about their defenses on some level, but they simply wish to keep this fact buried and pretend it doesn’t exist. A lot of people are offended by the notion that they even have defenses, which they regard as an insult for some reason. Perhaps they seem cowardly for not “facing up to reality” and using defenses to block and distort painful reality, which is exactly what defenses do.
I have had people physically assault me for pointing out longstanding (and very ugly) defenses that they have been engaged in for years. A number of times these resulted in actual fistfights or showdowns with deadly weapons (usually whatever heavy object happens to be lying around). Uncovering defenses is a dangerous thing to do.
I basically uncovered some of the dirty secrets of their life, the huge lies they have been telling themselves all these years in order to get through life by blaming other people and not themselves. Most people don’t like having their dirty little secrets uncovered. It’s enraging.