That flyer is completely deranged, even by the standards of SPUC (who raise the bar on derangement pretty high). It is, in terms, in the first paragraph, accusing the NSPCC and Barnardos of being active enthusiasts for the promotion of pornography in school contexts. Really. Seriously.
Depending on your mood and politics both organisations have done things you might disagree with tactically; neither was entirely blameless over the "ritual abuse" shambles, for example. But you'd have to be suffering from pretty serious delusions to think their hearts are anything other than in the right place, or that they do other than think pretty carefully about what they do. SPUC are putting the boot in on "Planet Porn", for example: it this makes it look entirely reasonable and sensible. "The focus at primary school is getting children used to talking about their bodies, in particular how girls' and boys' bodies are different" is said as though it's a bad thing, too.
And then Elizabeth Truss is roped into the conspiracy. Elizabeth Truss. She's quite right wing, you know.