People who like it smooth simply cannot accept the truth that their orange juice is no longer real orange juice.
The smooth variant is made of concentrate, which is regular orange juice boiled down (where the pulp basically desintegrates as its structure is denatured). Next, more water and quite a good bit of sugar is added.
So give me, fresh orange juice which does indeed contain pulp and, like the good man I now quote says:
why would you skip out on the ingredient that contains the vitamins and such
So actually, thinking about it, whether you like it smooth or with pulp, there's always pulp in there, but not necessarily in its true form ;)