I don't think any of what he did was stupid. He wanted to do evil shit to children, he did evil shit to children. The shout-out was a boast, a dogwhistle to other monsters like him, and a thank you to the person who helped him torture children. To him, he was giggling behind his hand because he was getting away with it. He still hasn't faced any kind of criminal penalty, and it doesn't seem likely he will, if the American prosecutions for this are any indicator.