That's a bit misleading, because one of the few places G+ has gotten traction is among developers, mostly in the Google ecosystem (go figure). That's a big and important ecosystem, so it's not shocking that people from there would post stuff that occasionally is of interest to HN.

Facebook wall posts aren't used in the same way by the tech crowd -- probably mostly because they didn't work like blog posts or G+ posts until after G+ launched -- so they don't get HN links. But in other communities people definitely link to wall posts. I work in politics and it's not unusual to see a politico use their Facebook wall as a kind of proto-blog. (Sarah Palin, or some nameless flack on her team at least, is/was a master at this.) It then gets plenty of links from political media.