You're not. But they weren't that great parents to begin with. Regardless of when the kid's interest towards sexual things awakens, I don't think that parents' should encourage it too soon.
Well, I've seen parents who almost bought Ichigo 100% (if you're not familiar with the title it's basically an ecchi) just because the kid choose it based on the cover and they didn't bother looking inside. Maybe it was the same and they did not know what was inside the book nonetheless it's still weird.
that would explain it you're right
I can actually relate, when i was Young about 9 or sumn, my mim bought me nana , which is not a Ecchi , but should be showed to a 9 yrs old. She didn't even see it's content Just bought It and that was It. I stopped Reading It when i saw a uhm 'different scene'
Is it only me that finds it weird that the parents gave a book like that to their kid?