This isn't really what a Christian who understands Christianity thinks, it's a pale replica. God knows that mankind is fallen: men were created to be together with God, but then the fall happened and sin came into the picture. The part that you have evaded is that God is perfect and just, and sin has to be answered for.

I'm hoping I can give you a deeper understanding of sin and why it is handled by God how it is. You're correct, judging us on our own merits results in Hell. We are born with a sin nature, where we do the things God can't abide. If that was the end of the story, it would be a real bummer of a story, though. Instead, God decided not to leave us on our own. Mankind chose his own way, but God had a plan to reconcile the people he made and loved back to him.

So, the message isn't that "he's so wonderful that if you ask really nice, he'll overlook your sin nature." That totally misses the point. The message is "you are a sinner, and God can't be around sin. There is a separation from his perfection and holiness as long as sin is on us. But, there's a rescue plan. It's God himself, as a person, and you just have to believe that he is who he says he is, then he takes on the punishment you should be getting, so that everything can be put back to right again." There's obviously a bit more depth to it than that, but that captures a lot of the essence.

It's not this shameful, pessimistic view that you're talking about. It's a rescue plan, and it's love because we could have just been left on our own. It's a free gift that anybody can take or leave. Most of this subreddit is on the "leave" side of the coin, but that's what God's really all about. God doesn't need anybody to be happy, he just lets you come along if you want to be there.

So also, yes. I do teach my little children this stuff. Every night, I tell my two year old about how the world isn't really how it was meant to be, but God is fixing it. Jesus loves him, and he made a way that everything is going to be made right again. It's hope, not guilt. You can get the point of the message and disagree, and that's fine. I just wanted to make sure you, and whoever else may come upon this, have a better understanding of sin before you make judgments based on the doctrine.