So while this surely raises attention for the issue, I'm not at all sure if it's a lot more useful than that.
The MPC has a somewhat unintuitive but very rationally consistent theory of criminal guilt. The MPC focuses on personal culpability. It finds someone guilty of an attempt when: 1) with intent to commit a crime; 2) he proves himself willing to carry out that intent by taking a substantial step towards committing that crime. The focus is on subjective culpability: what the criminal is thinking and what actions he takes. The focus is not on what happens.
Thought experiment: three people go out and buy a gun, and take a shot through an apartment window at who they think is their ex-wife. First one hits and kills her. Second one misses because of a sudden gust of wind. Third one hits what turns out to be a mannequin. From the point of view of moral culpability: aren't the three people equally guilty? Each had the same murderous intent, and each took exactly the same actions to carry out that intent.
Now, if you think the three aren't equally guilty, because the same thing didn't happen in the three cases, consider this hypothetical: three men are driving down the road. They see their ex-wife at a bus-stop. The first man is driving very carefully, but drives over a nail, blows out his tire, and veers into his ex-wife, killing her. The second man is playing a video game on his iPad, and veers into his ex-wife, killing her. The third man is still bitter from the divorce, and veers into his ex-wife on purpose, killing her.
If the focus is on what happens rather than on what the actor thought and did, should all three be prosecuted as murder?
Is it naive of me to say that you should weigh in both the outcomes and the intentions to determine the degree of punishment?
So in the first case, the guy who actually hit his target gets a more severe punishment than the other two.
In the second case, the guy who demonstrated clear malicious intent deserves a more severe punishment than the other two.
I suspect the answer is "both", but I'm leery of using criminal law to enforce consensus views on how one should think. I'm far more comfortable with using the law to address actual harm than to punish the desire to cause harm or even an attempt to do so. I realize, however, that there are many cogent counter-examples: being convicted of drunk driving does not require you actually hurt someone, trying to buy drugs in a sting does not require there actually be drugs present, etc.
"Thought crimes" refers to punishing people for (1) only. But just because (3) is lacking does not mean we're talking about "thought crimes" so long as (2) is present.
Second, the purpose of the criminal law is not to give redress to victims. That's the purpose of the civil law. The purpose of the criminal law is to punish those who are morally culpable and to create societal norms certain kinds of behavior. That is precisely why (3) is not necessary to prosecute a crime.
The purpose of any law should never be to punish the culpable. It may very well be reasonable to punish the culpable if it results in normalizing societal norms by way of a threat deterrent ("if you do crime $x, you'll get locked up just like this bad boy here"), but simply punishing a criminal for the sake of punishing -- hurting, torturing, locking up -- is an idea that I don't think stands to any thoughtful, philosophically-informed scrutiny.
I think if we get over this type of thinking society will improve. Now and then whenever debate about capital punishment gets picked up, people point out something about the histories of serial killers: almost invariably they've had particularly shitty childhoods, they were born to drunkards and criminals themselves, they were abused -- sexually, physically, they grew up in cultural filth, they had virtually no access to opportunity. The thing is, thieves, sexual predators and other folk who do sometimes petty crime aren't greatly dissimilar in this respect, they've also been enraged to some point to lose a sense of control, to lose respect for themselves and others. So to reform society for lasting good, the idea of punishment -- that you should make someone suffer -- is totally wrong. Instead we should should have social programs that hook criminals up with psychologists and therapists, see what's wrong, what's bothering them, give them a dignified place to live, and let them heal and let them rejoin society when they're better.
After all, this strategy works and gives good results where it's been tried: http://www.theatlantic.com/international/archive/2013/09/why...
Also, intent and thought are not the exact same thing in legal terms. For example, I have certainly daydreamed about robbing a bank - not because I want to take anyone else's money particularly, but because it's amusing to imagine what sort of clever tricks you might employ to pull it off. I'm sure you've noticed there's a whole genre of movies and crime novels about likable criminals pulling off an elaborate heist, doesn't mean the film production people or the audience that enjoys the films actually want to take up a life of crime.
Now if I start making all the preparations to commit a robbery - enlisting co-conspirators, or acquiring weapons, or suborning employees of the bank, etc. I've obviously gone quite a way past simple daydreaming. Such acts are demonstrative of my intention. Picture yourself sitting in a car outside a bank, with a bag on your lap that contains a gun, a ransom note, and a mask. You'd obviously be in a very different frame of mind from someone who was simply musing on the general possibility of robbing a bank, and a prosecutor would certainly be justified in asking a jury to take that into account if you were on trial for attempt or conspiracy.
Under this reading, the mechanics of how you choose what to punish don't really matter, so long as the result is closer to what you want.
Granted, we might want to live in a society where thoughtcrime isn't a thing, and this might shape the laws we create, but collective processes can be considerably less rational than that.
It's possible that these laws are different in the Netherlands, but even then, predators located in the US may not be protected.