"But she was merely posting an innocent thread about a book she got from her mum and was only after a discussion about atheism, wasn't she?"
How would you tell? How could you tell the difference between a troll posting a WOHM thread and an innocent poster not seeking to stir up a spat?
Given that she is only 15, it is possible that she was merely naive. Btw, she did know about karma whoring, she mentioned it in a post.
"Which isn't without reservation. "
No, you're (deliberately?) misreading my posts. I have unreservedly many times condemned the rape threats. But other comments that were not strictly on the topic of atheism are a different matter.