The gaffe is not what this is about. The extremely strong reaction is because the GOP establishment does not want abortion discussed in this election. They don't want to admit to their base that they are pro-abortion, and they don't want to be on the record as being anti-abortion, because then they might have to actually stand up for that cause after being elected. For the GOP elites, the less said about abortion, the better, because they passionately want the status quo to remain on that issue.
I completely agree with your post. If Mittens gets elected as the next President of the US, will he be the same as Zero? The Republicans are fast becoming what I very much dislike about the Democratic party.