Chaos
No-one has answered your question on why the "authorities" can't just block the dark web but in case you are still wondering, it is, in simple terms, impossible. Surely you cannot seriously think that could be done?
Law enforcement agencies would need to monitor everyone with a computer. It is just not possible. There are probably far more detailed explanations you could find on google search engine if you care to research that. The dark web is not all for illegal activity either.
Please, you and other posters, stop going on about Thompson not having committed other crimes unless you qualify that statement with "as far as we know" or such like. I posted earlier on this thread to comment that the probation system is not without flaws / problems. It is not designed to nor is it capable of watching / monitoring anyone 24/7 and guarantee that they are not offending in some way. That is why we have 'experts' to identify / assess and recommend on risk and management of those risks.
It has clearly spectacularly failed in Venables case. In 2010 and now again.
There is no guarantee at all that joe public would know if Thompson had reoffended. Possibly, and that is not a definite either, we would know if he was brought before a court for prosecution, but despite being on life license and all the conditions attached to that, he could still be offending "under the radar". Just not getting caught.
I think some people on this thread and just generally too think that police forces, the national crime agency, etc have unlimited resource, power and reach when it comes to identifying and apprehending sex offenders. They don't. They rely on intelligence gathering from many sources and techniques, many quite sensitive and many of which will never see the light of day in a UK court of law. They have to get a case to court by gathering sufficient evidence to withstand defence attack, then the prosecutor needs to convince a jury, they can have all manner of evidence ruled out and deemed inadmissable, they have restrictions on what they can do within the bounds of the law, application of the ECHR, far from unlimited resource, etc etc etc. Intelligence does not always convert to evidence. Someone can be as guilty as sin and the dogs on the street know it but proving it in a court is another matter entirely.
You refer to people singling Venables out due to the nature of his previous crime, presumably you mean when he killed James Bulger, and you have forgotten about his 2010 sentencing for sex offending, or is that not relevant?
How many chances should he get? I think the key should be thrown away where he is concerned.