Oh I'd be furious and jump all over that one. Private property or not, if that's their policy it needs to be stated very clearly with signs everywhere. And does the bus company know about this policy? If not, get them involved too since it hinders their passengers from catching their bus. Maybe they move the bus stop just off hospital property.
Grrrr... that makes me angry right along with you.
Power trip indeed... report him (especially with the assumingly condescending tone when he told you to "now turn that bike around and go back the way you came." OMG