Earlier quoted context omitted.
https://law.justia.com/cases/massachusetts/supreme-court/201...
I'm not sure that's what you meant to link to. The description there is beyond lurid, and that guy only ended up on a registry after a lot of shenanigans.
He is appealing his placement on the registry on three grounds:
1. He can't be guilty of a qualifying offense, because he has no prior conviction;
2. The officer who put him on the registry did so solely on the basis that his risk of reoffending was "moderate", when it was also necessary to find that he posed a "moderate" danger to the public;
3. He did not in fact pose a danger to the public.
And the judgment rules against him on argument 1 while ruling for him on arguments 2 and 3, nullifying his registration.
Given that this judgment overturns a judgment below, it is evidence that you can be placed on a public registry for purely spurious reasons. That's what happened originally, and it's what was affirmed in the judgment below.