I have been guilty of saying these exact things in my first year or two of teaching. That was, until I had my "A-HA" moment. I asked myself, "what are the children learning by me doing it for them" and "what is the worst that would happen if I let them hold and glue for themselves?"
So I let go and let them...and they puddled the glue, and it seeped all over the table and floor, and soaked the papers until we could no longer move them. But something else happened. They had fun. They began to understand that if they used to much glue the project was immovable. Their hands became stronger, their muscles developed, they learned to control the amount of glue they intended to use. They learned because I provided the materials and let them explore, discover and make mistakes. Something else happened too. I learned. I learned that I do not need to control the materials. I learned that I do not need to "help" them. I learned to sit back and give them control over what they created and they learned responsibility.
I understand there are budgets to keep to and it can seem wasteful to let the children puddle the glue in what seems to be a senseless act. But it isn't senseless. They are learning, as children do, by doing, by experimenting, by immersing themselves in the experience. Compared to the experience, glue seems cheap.