Was it wrong for me to tell my x son that santa claus is not real?

I believe in telling children the truth. I have no children of my own but my x has two sons and one day her youngest son came and asked me about Santa Claus and I told him the truth. I did not go around the corner with it or ask him what his mother and dad said, I told him that Santa Claus that ride around in a sled does not exist and that 95 percent of Holidays are made up by man. I did tell him how Christmas came about but that Santa Claus was as real as the easter bunny and the Jack O lantern. When l was done he went and asked his parents was what I said was true and they told him the truth but was very upset with me. I was 9 when I learned that Santa Claus wasn't real when I was giving an options of choosing a white Santa Claus and a black Santa Claus. the first thing that came to mind, ok so if Santa Claus isn't real and the easter bunny isn't real, then how do I know that God is real. so parents please, do not lie to your kids. cause if you lie about one thing, they may believe you to lie about God existence.