Quoting Ryloonjimama:" Since your kid knows he's not real, what difference does it make if someone says he is? Whereas, a kid ... [snip!] ... the worst at being Santa anyway, so my kids probably won't even be surprised. LOL It's just a bit of fun while it lasts."
It makes a difference. So someone who is Jewish has to hide their beliefs in no Santa just because someone doesn't want to explain to their kid they've been lying to them? Yeah, I don't think so.
I know in our son's case and in the case of the moron teacher last year, Will had known from the beginning Santa wasn't real and it was just a fun story. But he was 4, and impressionable. Having a teacher, the teacher's staff, and his classmates tell him Santa was real, go through the motions of writing to Santa and then bringing in Santa to class was enough to thouroughly confuse him.