That’s true only in that without pollination they don’t produce fruit. So any that they make is bigger than 0 
Check out the study from Prof Yao. She tested a number of different jujubes and most produced no fruit when blocked from pollination. Only Li and a few others can do it.
Most rootstock fruit is pretty poor. Here’s one of the better ones I’ve had. While better than most rootstocks, it still had quite poor texture- pretty dense, but not crisp like Sugar Cane or Honey Jar. It was however quite productive and could get to high brix.
Here’s another rootstock which wasn’t too bad. The fruit is a bit more sour, but still palatable. And the tree is very productive (the other varieties grafted on it, not just the rootstock). I should probably try to propagate the rootstock and see if copies of it do just as well.
Green cuttings can work, but it is quite difficult. I haven’t had any live, but Tony has had some success. Grafting is a much more reliable way to spread jujubes.
You would want to remove most/all rootstock growth under the variety that you want to grow. Otherwise, the tree will get taken over by the rootstock, which isn’t a good thing.
On the other hand, healthy mature trees can send out suckers 5-10 feet away from the tree. I don’t think that is really a sign of a problem. You can let them grow a bit and eventually harvest them to graft to. I’ve grafted them in place, which works until the rabbits find the nice new growth.
You may want to check out my 2 large jujube year in review posts: