Well, firstly, it's not wise to try and fault with bishop's council. I am sure his request for the comfort of those around. Secondly, here in the States, when women breastfeed, they tend to cover up with a blanket over the child and shoulder. I live with my brother and his wife who is now breastfeeding. She covers when I am in the room. I don't know if you are covering up or not. But I can tell you, that if you are not, from a male perspective, there will be a few teenage boys that might be more willing to offer you the sacrament when you are breastfeeding. No matter how beautiful the act of nursing is, it still exposes a body part that can excite young boys (and older)
However, if you are indeed covering up with a blanket over your child and shoulder, I don't see the problem. We may not agree with what are bishops say, but it is our responsibility to listen and heed their council. He may have a perspective on the matter that you don't. Some people may have complained about the act. He needs to take the concerns of others in consideration. The last thing we need is our priesthood holders to lose the spirit of the sacrament over an exposed breast.