I have to disagree here. Everybody is free to give presents and the moment they give them away it is your choice what to do with them. I refuse to sit in a house full of stuff that I hate to see and there are toys I don`t want my kids (I have 3) to have.
You have a right to sort out and throw or give away. Other than what has been said here I do not think that because I give something to someone I have the right to insist the Person is using it. If I really care for the Person to like what I give them, I ask.
You as a mother will decide for a very Long time now what your child will be surrounded by. The movies they watch, the Food they eat, the clothes they wear, the education they get. In my eyes yes you have a right to also decide which presents they get and which ones leave your house right away.
With close relatives you might want to discuss how you handle things in future. I tried it with my mother in law and failed as she insisted on her taste being best. fair enough... but the stuff she is giving goes to the charity shop right away.
Your house, your taste... at least until your Baby developes one of her own...