It wasn't necessary. I guess some governments figured it would be a nice gesture, only to have it blow up in their face. But the fact remains that the people had little or no idea what they were voting on, and voted out of a general dissatisfaction and hesitation regarding the EU as a whole. A valid concern, but not the issue at hand.
I understand your objections, and I share a lot of them, but there will be no going back on this one.