The reaction can be partly explained by the sense of attack on our previously fond feelings. Watching the new movie automatically calls up memories from the previous series and all the pleasant childhood playtime memories associated with it. But recalling these fond memories in the context of a negative experience begins the process of re-coding, or modifying our old memories. This is an undesirable outcome for nostalgia as it is usually such a pleasant feeling. Naturally there is some resistance and cognitive dissonance when this happens and the brain will try to avoid it like any other unpleasant experience.
So, George Lucas did rape your childhood… From a certain point of view. Ouch.
Alas, it really can’t explain why I spent the late 90’s calling for the head of Kevin J. Anderson… Or does it? We all have our demons, I suppose.