As we were playing one kid called another an idiot to my dismay.
I am curious why did you get dismayed when a kid called someone else an idiot?
Because idiots shouldn't talk, they should be quiet and stick to doing things like maths.
Well, kids will never be nice all the time and that shouldn't be an expectation of yours. While they shouldn't be calling each other idiots, it sounds like you're calling them idiots right now. Maybe reevaluate how you think about people and you'll be a lot less upset all of the time.
I don't give a shit what you think. I'm right, I've experienced it.
Even if you have experienced what you did, it doesn't make you right specially if you're being upset about something that is not targeted to you. Being an adult, you need to be a role model to these kids, and you should have reprimanded the kid who called someone an idiot and say that is not the nice thing to do and gave them a lesson. I hope you find less anger in your heart moving forward.