Their names look very Dutch to me (I'm Dutch myself), so I'm guessing the Netherlands (or perhaps Belgium).
You're probably right that "encouraging people to rob a specific person's house is actionable in every first world country". However, that's clearly not their stated intention - to the contrary, in fact.
In the Netherlands, if someone would start a lawsuit about this (could happen, sure), I'm guessing chances are pretty good that the judge will buy the argument of the website authors, especially since burglars can already trivially find the exact same information if they have two half-working brain cells, and their stated purpose is to actually make people aware of this obvious problem. In addition, whoever starts the lawsuit would probably first have to prove actual damages (e.g. being robbed), and that this was caused by this website, and even then there's the obvious counterpoint that they put this information online themselves in the first place, and it might have been trivially found without that website. The apparent intention (of the website authors) matters as well, probably more so than in the USA (this is just a feeling, I may be wrong).
So, it's hard to prove that a robbery was "caused" or "encouraged" by this website, even then it involved your own stupidity in putting that information publicly on the internet in the first place, therefore the chances of winning (as the person who got robbed) seem not that great. In addition to that, mostly everyone here has insurance covering their household effects, meaning they'd get (most of) the money back from an insurance company anyway, so why bother with the lawsuit.
Finally, if you lose, you typically have to pay the legal costs of the defending side - so starting the lawsuit is not without financial risk in the first place.
Much of this is probably also true in the USA, but the legal costs involved would be higher, and I somehow have a feeling, also the chances of losing. (IANAL, so I may be wrong about that.)