A substitute teacher did that to me when I was that age. If someone did that to my kids I would be pissed. Give that topic to older kids, not the ones that are likely to still believe.

What? they aren't real?

My teacher told us at 12. We all already knew. I found out myself when reading a book on Santa (or really the Dutch slightly racist version Sinterklaas) where it was said it's celebrated on the day he supposedly died.

Wow. I would say 8 years old is still a reasonable age to believe in Santa. I imagine that was the first and last time the teacher used this particular activity.

Do kids even believe at that age?

I'm sure many other parents would be complaining as well. Poor kiddies :(

I didn't find out until I was 12. Which was shocking because my older brother is an asshat. But I believe children should learn this on their own. Someone (especially outside the family) telling a child that something they believe in isn't real is just unfair. When I found out my mother got me to calm down by telling me the dutch story. And that gifts from Santa is just a way of keeping him alive in our hearts.

I want to tell an extreme christian that God isn't real and make him/her cry.

That's beyond ridiculous, you need to speak to his/her superiors and then after you've gotten him/her in trouble, go talk to him/her yourself and that's the kind of situation where you're allowed to be the excessively angry parent and totally lose your shit.

Ahh..gotta love public school. It's like an indoctrination center to brainwash you to believe what they think.