based on what do you claim that it's not oneway up to hospitalgasse?
there are no driveways in the section and so the rule of it being oneway stands until the junction with hospitalgasse at which point people coming from either side of hospitalgasse have no way of knowing of that restriction ergo it's lifted. So what are you basing it on that it's not the case up to the junction?
The above explanation is at least the one given to me by my driving instructor when I made my driver's license in Germany.