Criticism is something we spend a lifetime trying to avoid.  It keeps us hiding and playing small and we end up not being our authentic self for fear we may be judged and criticized.  This is the primal part of us responding this way, it’s that part of our brain which is concerned with survival.  The threat of not belonging means isolation from the pack and when we sit on the fringes of the herd in having been cast out, we’re vulnerable to prey.  So it’s going to be this natural default primal response that induces the fear and anxiety around judgement and criticism. 

Secondary to this is the need for our ego or false identity we’ve created for ourselves to come to the rescue and protect us. When someone is in a position where they criticize or judge you, this part of us thinks that unless we step in to defend ourselves, then our status and worthiness as a person is under question …which places them in an attack position…. which we feel must be defended or otherwise we’re condemned to being less than or unworthy…which is going to be too painful for most of us to identify with…. and so we feel the need to do whatever we must to avoid this outcome.