Systemic Insecticides Applied to Fruit Trees Does Not Make Sense to Me

I am very concerned about an insecticide I applied to my lemon and pomegranate tree....
Q. Your newspaper column really caught my eye and I am very concerned about the coming fruit on my Meyer lemon and pomegranate tree. I was having a problem with something eating my lemon and went to nursery to purchase the dormant oil to ward off insects. The nurseryman told me I was too late to apply it and must apply Bayers Advanced Insect Control at this time of the year. 

So the same day, February 25, 2012, I applied 1 oz. to the lemon tree and 2 oz. to the pomegranate tree. I believe this is a systemic insect control as it is only applied once a year and the nursery man had said it goes up through the stems.  I am very upset as it appears we will have a good crop of lemons this year as well as pomegranates and I will be afraid to eat any. These are both young trees.  

A. This particular insecticide is a soil applied conventional, systemic insecticide. Systemic means that the plant can take up this insecticide, transport it through the trunk and limbs to branches where it provides protection from insect attacks.

It is labeled as an application for controlling insects on FRUIT BEARING fruit trees. The federal government has approved its use for these purposes. 

Now for my opinion. I would never use a systemic insecticide of plants that produce food regardless of who or what approved it. This, to me, just does not make any sense at all. Personally I would not knowingly eat fruit produced from trees  that have been treated with this type of a product. Use on landscape or ornamental trees is a different situation.