Maybe the problem here is the word destigmatise?
I believe that anyone who has never committed a crime, but who fears that they might because they are drawn to committing the crime, should be helped NOT to commit the crime, especially if the crime is really serious and would have a devastating affect on the victim.
Can we all agree that? Please can we all agree that?
So the next question is about a subset of people who have not committed a crime (or rather no-one has evidence that they have committed a crime). They are drawn to committing a really serious crime, and the only way of identifying them is if they come forward (or if they commit a crime and get caught). We have already established that we need to help them (for the benefit of the victim if no-one else), and we know that the only way we'll help them is if they come forward?
Surely we can all agree these potential sex offenders should come forward?
How do we achieve that? Surely carrot (and I prefer destigimatising people that givign the cash payouts for coming forward and admitting their perverted thoughts) or stick.
Just about the only alternative I can think of to destigmatisation to help acheive very sensible aims would be to have a two-tier sentencing system, whereby paedophiles who were registered as such, and were actively seeking help, received lower sentences than those who had not reached out for help. This could be acheived by using current sentencing guidelines on paedophiles getting help, and having tougher sentences for those who have not come forward.