The things you mention are already illegal. The effective proven solution is to enforce existing laws, to punish and deter bad behaviour like any other crime.
This incongruence is why a lot of people don't take the reasoning at face value and see it as only rhetorical justification for increased surveillance, which is widely understood as something the state wants do do anyway.
> How do you deal with a crime that isn’t reported due to things like shame?
You don't.
Perhaps His Majesty’s Government could establish mandatory thought scanning using cutting edge technology[0] to ensure that no crimes go unreported due to shame, dishonesty, or threats. Just step into the scanning booth once a week, a minor inconvenience to ensure your safety. Surely you have nothing to hide?
I posted a reply here https://news.ycombinator.com/item?id=46599842 that addresses why I think "this is already a crime" doesn't go far enough, and why these laws are being introduced.
How do you deal with a crime that isn’t reported due to things like shame?
Not to say that we need to scan messages to enforce nudes not to be sent, but I don’t think you can say “just enforce existing laws” and be done with it, it’s not that simple.