The justification is that in nordic countries it is OK to walk and cycle on private land, and to stay for up to one night. But if access is NO then it is no, unless someone has a key/permit. Also, this is not literally private property, more like a municipal facility.

Practically, I'd like to stop Garmin toys and brouter.de to stop routing my bike rides through the garden. The gate in question is very much closed and enforced with barbed wire.