I actually don't believe for one second that sex with children was open to rational debate in the way that sex before marriage, cohabitation, gay sex or pornography was.
The significant difference, of course, is that the above were at least between consenting adults.
Why are people making out that people in the 1970s were idiots or something? Idiots that didn't know the difference between the actions of consenting adults and children?
It's like saying that just because people then were 'meat and two veg'* kind of people they might be open to persuasion to eating a bowl of spag bol or mussels (spag bol=cohabitation).
What the PIE debate was doing was asking people to consider eating maggots.
I honestly think most people would have dismissed it out of hand without any second thought.
And I don't believe that a left-wing organisation would allow far-right groups to have their say, either. They're not the 'let everybody have their say' egalatarians people are making them out to be.
You criticise the Harriet Harman's of this world about stuff like gay marriage and you'll be soon shut down and called a 'bigot' . Sex with kids, though? Oh yeah, that sort of person will hear you out on that one. 