Why is some garlic labeled Not For Planting?

Why is some garlic labeled Eating Garlic, Not For Planting?
We have found a few diseased bulbs in our garlic plots (White Rot, and garlic nematodes). Although the diseased bulbs have been thrown out, there is a chance that a trace could be present on the garlic we are selling. These could infect your garden soil (affecting only garlic, onions and other alliums). This doesn’t affect the quality, flavor, health benefits or storage life of the garlic we are selling.

We recommend that you don’t plant garlic from our farm if you grow on a large scale, or plan to sell your garlic. If you do plant it for your home garden you should do a hot-water soak before planting

We are working on trying to eliminate or reduce the disease using organic methods, and have had some success in keeping symptoms to a minimum. Our newest field is clean with no sign of disease.