Harry Potter isn't real and I'm going to let a lunch room full of children know the truth.
What would motivate you to tell kids that Harry Potter isn't real?
I think they should know that he never existed.
Believing in fictional characters can benefit children's development as an avenue for creativity, imagination and play. Crushing their spirits might make them not want to read as much anymore.
It's fine if you disagree with me. I'd rather say harry potter doesn't exist than see kids grow up in the same delusion I was in.
I'm sorry you feel your experience wasn't good, but it's awful to crush the imagination's of children. Let them enjoy the only time in their lives where it's okay and exciting to believe such things. It's not your place to tell them such a thing, not to mention it's quite rude.