Your reading comprahension is somewhat lacking.
The question posed wasn't actually whether UK should exit the EU or not, but rahter:
1. Remain in the EU (championed by anyone sane with no narrow self-interest)
2. Leave the EU, but remain in the Common market (champioined by some big businesses and the like)
3. Leave the EU and the Common market (championed by various insane groups from extreme left and right)
The referendum question grouped 2. and 3. together, although they lack any common ground beyond the obvious "leave the EU". That's the easy part, the hard part is what comes now. Options 1. and 2. are far more compatible, but were pitted against each other. Well, what is done is done, but now it really should be determined if UK needs to shoot itself in the foot with a 5'' gun and go for the Norwegian style Common market, or does it utilize the 15'' gun and leave the Common market altogehter.
Since much of the Brexitard campaign was based on points that necessiate leaving the Common market, without telling that loudly and clearly, a referendum on that is probably necessary.
McHrozni