From a pedestrian point of view ... I find it rude to be bellowed at by someone on a bike. Also, if he/she is so near me that I can hear them without them shouting, that IMO is too near...
I'm not disagreeing with your overall post, but; my usual practice (depending on the width of the path) is to roll up behind someone and say "excuse me" - I think that shouting from further back is rude, and prefer to use my voice rather than a bell as I feel that is more courteous. Are you saying that you object to a spoken "excuse me" from a stationary or near-stationary cyclist?
I also run and I'm still perfecting the best distance to call "excuse me" from if I need to warn someone of my approach - too near and by the time the pedestrian has realised what's behind them you're on top of them. So is has to be further back and a bit louder (without sounding rude - and it is of course harder not to sound rude when you're running as you're out of breath! You shouldn't be cycling at a speed that will make you out of breath on a shared use path, IMO).
To be honest, I think we as cyclists can't win on shared use paths - no matter what we do, someone will object.