My state has a "FLAP" law that applies on divided roads like this. I ride FLAP all the time when approaching a desired left turn in this situation. Like on this road, there is generally a yellow line and about a foot of shoulder area left of it. I ride on or near the line and never have had a problem, at least, never more than when riding on the right. Insisting on "taking the (left) lane" on at least one of my routes would probably be a death wish (besides being illegal AFAICT).

I suspect OPs problem may have been he was startled by the horn and it could be (wasn't there so no way to really tell, just a possibility) that had he held his line, all would have ended well, though with the muttered "eff you a hole" (I am trying to avoid giving the salute on these).

scott s.
.