Jay -
Were other people on Unicom/CTAF? Was the cessna the exception?
Maybe your radio was tuned wrong? I doubt you want to play Mr. FAA but
if you have others with you on this, you might have a stronger case.
Is there a FAR that states Part 135 have standardized CTAF or could
they claim "oh, it's an uncontrolled field. I can do anything including
shutting off the radios in my $18 million spam-can smashing jet."
Generally, on approaches into uncontrolled airports, I'll make
regular radio calls. At times it gets busy as hell and I might skip
one or even two. Pre-departure the workload is a LOT less so not
making radio calls is kind of silly.

I still remember on my PPL checkride on 12/17/03, everyone
and their mother was out flying. I had a C182 position and hold when
I was on a 2 mile final for the simulated engine out. I was just about
to go around and cancel/postpone that section of it when the guy started
rolling. Uncontrolled airports really scare me. I'd rather have
"the voice of god" commanding aircraft around.

Gerald