Saying No to Electronic Toys

When my son was born, I told our families that I was not interested in plastic/electronic toys. While visiting my in-laws, they excitedly brought out a plastic electronic car that sings and beeps. I thanked them and told them I wasn’t interested in this type of toy for my 17-month-old. They became defensive and accused me of delaying my son’s development. They seemed sad that I wouldn’t let him play with these toys even at their house. I feel strongly about the need to foster imaginative play and my life choices reflect this need. Am I off base?