So let me get this straight.
You humbly told everyone who got involved that it was a game and should not be taken seriously.
Then, this guy frames you for pedophilia because he let his daughter on the internet.
He let his eight year old daughter go on the internet.
I highly doubt it's your fault, and as any normal person would agree, having small kids on the internet, no matter how or where, is a bad idea. Hell, I've even seen sexually provoking pictures of Dora the Explorer! I'm terribly sorry for what might happen to you, but from my point of view, he's just a bad parent.
But still, with all of this, I suppose it shall be a good idea to bring up an age restrictor, like Crona the Critic suggested in a different topic. It might not stop kids from getting in, but at least members of this website will be protected in some way from cases such as this.
Edit: Ok, so apparently, he did supervise her. Still though, jumping to conclusions and then threatening other people like some idiot with not even the slightest of remorse or giving the ability to explain the whole situation.
Yup. I still blame the father.