Why is my Little One Saying, "What the Hxxx??"

In these days of the Hell Challenge, I started wondering where kids learn it from

When I was in first grade, I remember quite vividly being outside during morning recess with my "boyfriend" (yes, kids are talking about these things at this age) running around and enjoying life.  I remember someone coming up to us and asking what I thought was a ridiculous question.  My reply was "Hell naw!"  And boy, virtually everyone on the nearby monkey bars within listening range took over from there…."Awwwwwwwwww!  She said a curse word!"  Of course some practically fell over themselves trying to get to the nearest teacher.  And of course, my freedom was taken from me- or at least my recess freedom.  I had to stand on the wall for the remaining recess periods the duration of the day.  I remember how puzzled I felt.  My parents, who both had leadership roles at our church, had told me that hell was where you were going if you were not saved. I'd heard my mom say the phrase many times before so I figured there should be no problem in saying it.  So why was I missing my recess? Were these people such heathens that they couldn't stand to even hear the word describing where they might be going?  These thoughts swirled around my mind all day until the teacher told me that I could participate in the final free-time activity if I'd apologized.  I stood and gave a very enthusiastic answer:  NO.  I felt I was indeed the victim.  The teacher, sensing that I was not feeling apologetic about the matter decided to call my mother.  "I guess I'll be letting your mom know then," she said confidently.  My mom was very active in the school PTA group so the teacher knew I'd change my act once my mom got involved. Surely, she'd knock some sense into me.  Imagine her mouth dropping when my mom said "We don't believe, or teach her that hell is a curse word. It is simply where the unsaved is going."  The teacher gathered her jaw from the floor and tried to regain composure and control, "Well, we do not approve of that phrase in school."  

My mom told me just not to say it around school anymore.  I always had better sense than to say, What the Hell around my mom, so I never had an issue with that.  I understand that the phrase might have a different connotation, so I didn't dare use it until I became an adult.  But my 3 year old son has decided that saying, 'what the hell' is his new choice phrase. Where he learned it from? I cannot pinpoint a direct source. But since he's started using it, my ears have been sensitized, and I now notice that so many places use variations of the phrase. Some had me a bit surprised.

• Grandparents - this one isn't surprising.  My parents have always said it.  I've asked them to refrain until my son matures, but understandingly it's been rough for them to reverse 40-50 years of saying a phrase. 
• Disney - Now this was surprising.  While watching his favorite movies, Cars 2 and Toy Story 3, I heard the phrase, "What the…?" multiple times.  I believe Mater says it multiple times, but I know he says it when the computer is changing his disguise to a 'monster' truck, and on Toy Story 3, the janitor of Sunnyside says it while in the bathroom cleaning.  Immediately, my son repeats it.  They seem to like phrases that express emotions at this age, and oftentimes learn those words or phrases first.  I've even heard the phrase used during a Disney Jr. cartoon. 
• Other kids at daycare or school - As kids learn from adults, they widely use what they've learned with or against their peers in this setting.  Chances are that your child will pick up one or more of those bad habits.
• Your daily news channel - While watching the latest "Breaking News" an analyst used the full-out phrase, What the hell.  And who was right there with me to instantly repeat it?? Yep, my son. What the hell?!  

What do we do now?  Well I spend a good 1-2 minutes directly after hearing my son repeat the phrase trying to explain that it's not what we should say.  Although sometimes he still says it, he remembers quickly after that it shouldn't be said, "Oh, sorry mommy."  At other times when he's more alert, he will scold whomever said it in the same fashion I use with him:  "No Mater, No Grandma, we don't say, 'what the'…You can say, What?! Instead. " It works for now.  It's hard trying to tell your 2-3 year of child that using the word hell isn't appropriate for some people, when it's widely used around you.