Why do young children get homework projects when for such young children, the projects are actually the responsibility of the parents?

For very young school children, say ages kindergarten and first grade, when the teacher gives a homework project, the project is pretty much the responsibility of the parent. It is the parent that will remember to do the project, and it is the parent that will do at least 90% of it. So do teachers realize that (I am guessing they would)? If so, why do they give homework projects to very young children?