Why is their such a big debate about Santa?

I always believed in Santa when I was growing up. I had small presents from Santa and the main presents from my parents. That means I did appericate what my parents were buying me.
People say that they don't want their child to be sad when they find out Santa isn't real. They are sad for about a week then they move on. People say that it ruins the true meaning of Christmas. They are kids they don't need to understand yet. It's part of growing up to have an imagination