Firstly, whilst I am not particularly surprised by either the moral panic which has been successfully whipped up or the uniformity of views expressed about this, it's far from clear to me that it is or should be a closed question. Indeed, I rather think that if it is decided, it should be decided in quite another direction. The man whose case initially sparked the controversy had admitted guilt, but not in a criminal trial. He has no conviction, as I understand the law, for child sex offences, and there are reasons quite separate from those of innocence or guilt for accepting a caution rather than going to trial, just as presumably the police had reasons for choosing to offer the alternative of a caution rather than going to trial. The question of his guilt does not thus seemed wholly settled to me.
Further, and more importantly, even if his guilt was a settled matter, the assumption that that guilt automatically rules him out from ever working with children seems to me obviously wrong. One drunk driving offence, an act which can negligently take the lives of others, surely a more serious wrong should it occur than looking at child pornography, does not prevent someone from ever using a car or drinking again. As a punishment for the offence, being barred from any employment which involved children seems to me disproportionate, because it denies the possibility of reform. To deny the possibility of reform is to deny the possibility of agency, of control over the direction of a life, and, close as much of the coverage of such cases does come to doing that, surely if paedophiles did totally lack agency, we would treat them quite differently, as one would treat dangerous animals or the criminally insane. Of course, it would incredibly careless not to make assessments of whether or not reform has occured, but since, one hopes, qualified professionals have judged that this man was neither criminally insane or a dangerous animal and did not pose a risk to his charges, maybe we should extend some trust to them and to him.
Postscript: Shuggy further demonstrates his clear and well-argued views on this matter here, and Aaronvitch Watch has two related pieces here and here.