???? You'd do that, especially as a former teacher, rather than have a reasonable conversation pointing out that some children he teaches may still believe this (any given) mythical character actually exists, and that, really, school personnel shouldn't usurp the parents' decision when to introduce the child to the truth?
Really?
If you read the OP's subsequent posts, the information was actually shared in a discussion about leprechauns. It wasn't in response to a direct question about ANY real or fictional character.
Respectfully, not mine - and I've been American all my life. AND I'm not alone. There are millions of us.
By pointing out that a teacher with any sense at all could have "danced around a direct question" I was trying to draw attention to the fact that indeed this was NOT even a response to a DIRECT question, which might have momentarily put the teacher on the spot. Nope.....This teacher entered the Santa minefield of his own accord. He chose to bring Santa into the conversation when he could have easily been left out. Fairies might have been safer. Better yet, some superhero. But I'd truly expect any adult who works with children this age to realize that many of them still believe in Santa and be sensitive to that. If he is truly this clueless, then yes, it would seem he needs to be snapped out of it to get the message. Subtlety likely won't work.
Sorry to say, far too many people out there, even in education, think it's their "responsibility" to enlighten children regarding such matters. They think they are doing them a favor. There is a certain smugness to it. Then again, maybe he's just a clueless dolt. In any case, before I left the room, I'd make sure he had a thorough understanding of just how seriously he had overstepped and want reassurance that he would never do it again. I'm not the sweetness and light sort when someone oversteps into my parental zone and brings a large part of our holiday traditions to a screeching halt before it was time simply because they lacked the ability to censor what came out of their mouth. You only get so many years of childhood innocence and that special Christmas morning experience. For some bigmouth to rob me of even one year would put me in a seriously foul mood.
You think that's harsh? Well, I think it's even worse that an adult was so unthinking as to have terminal case of open mouth/insert foot which would wind up screwing up the holidays for a lot of families. Maybe every American family doesn't have Santa as part of their Christmas celebration, but millions do. That should be respected. If he'd gone around yakking that some being/character/person from another culture wasn't real, heads would have rolled. If he had minimized the value of a treasured icon of some other culture besides that of America, parents would be having fits. And rightly so.
Long story short, there was no up side to him opening his mouth and "sharing." There was a significant up side to keeping his mouth shut. It seems that every few months, particularly near Christmas, you hear of some teacher pulling this stunt, often with very young children. I simply cannot believe they can say with a straight face, "Oh, it never dawned on me that I might be destroying a child's belief in Santa."
Puh-leeze. They know, yet they continue to do it.
So you didn't believe in Santa? Goody for you. That's your right. But my family has a right to celebrate Christmas any way we want and have that respected.
If, when I visited the teacher, he said something like, "Gee, I'm sorry. As soon as I said it, I knew I shouldn't have, but it was too late. I wish I could take it back. I won't ever make that mistake again," that would be another matter. But somehow I don't think that's the case.
.
Heck, if I'd grown up in this town, I may have believed forever. 
