Seems we have a pattern for this in Finland. DNS blocking of suspected child porn sites went live some years ago. Then a researcher published critique on how it was handled (most of the blocked sites did not have any illegal material), and his site got blocked as well.
The childporn system in Denmark was used to something similar. The actual list of websites is/was hidden, but got leaked to wikileaks -- a large amount of those banned sites were simply (adult) gay sites that had pissed somebody of.
I am not sure, but I think the end of it was that the leak was blocked too (since it contained addresses of child porn).
Personally I guess they just didn't wanted to have to explain why they blocked a site for a Duck forklift renting company (to be fair, those were some sexy forklifts, they were less than 18 and they didn't have much clothing on).
The ministry of purity has determined that your website offends the invisible powers that be. It has been purified. Thank you for your cooperation. This decision may not be appealed or challenged or examined. You may not ask how this decision has been reached because if you do, you would be exposed to impure thoughts.