OP if you are wanting intelligent and thoughtful....perhaps try and consider what is behind the views you don't agree with? Dismissing them as unintelligent is the easy option. Its easy if you feel yours is the morally superior view to think other views aren't valid.
A couple of things stand out to me...people wanting to know if there is a chance that someone who is a risk to their children is living nearby is being conflated with those who would commit acts of violence. Wanting to be informed is not the same as inciting violence. To lump everyone together is wrong.
And those posters whose comments shock - the "gets what he deserves" etc sentiment....well perhaps they are a bit disillusioned with the system?
Re the law - I live by the law - of course I do - because, well, society would be chaos otherwise. By and large I am a believer in our justice system. However....it absolutely does us let down in many ways - abused children, abused women, (record on rape is appalling), discriminates based on race.... it is not doing a fantastic job?! Indeed very far from it! So it is not surprising the public don't always feel confident.
Perhaps sharing information makes it harder to monitor those in the community...but only because we are attempting to manage offenders in the community who pose a significant risk in the first place. Then there is repeated reoffending, breaches of orders designed to protect vulnerable victims, repeated failures to comply with sex offender register requirements etc. I am fairly liberal when it comes to justice. Eg, I think the prison numbers are far too high, the prison regime is inhumane. BUT I also think that we do not sentence adequately to protect children. Deal with that and you will start to resolve some of the issues of mistaken identity. And protect more children.
And perhaps if less risk is managed in the community, people won't feel the need to share questionable unverified information on social media?
Re whether you would act differently if you had knowledge... I rather think you might parent at least a little differently. I definitely exercised more caution when I became aware of how many convicted sex offenders are in my local community. Only a little - mostly I just have to live with the risk. But i can understand people finding that difficult.
Thats my [long!] attempt at the more thoughtful alternative view!