Yeah it's nice that you're so considerate and it's definitely not unappreciated, but you're certainly in a small minority of cyclists in wanting those behaviors to be the norm. I'm confident that most cyclists consider those to generally be car behaviors and unless you're in close quarters with another cyclist or around cars, they're never really required and absolutely not expected. There is no world in which I'm going to want or expect other cyclists to be making hand signals meant to get the attention of drivers every time they need to make a turn, and so long as I'm not in a very tight spot on the path I'd rather that other cyclists pass me without having to make a ritual of it. Yours is definitely not an axe that most of us want to grind. Just so you're aware.

Maybe, but that's circumstantial.

What I said is just... fear of getting ran over because by the time you notice* the sound of the motor of an extremely heavy and fast vehicle approaching you it's probably right behind you. This logic also assumes you're getting over as much as you can (even totally off the road if it isn't a ditch) whenever you see oncoming traffic though. Either way, not preferred.

This was my own logic (not that I actually rode very much like that) until I got myself a mirror.

* also knowing that it's approaching you, not going some other direction

My point is just that there is some reasoning behind it, even if it isn't preferred. As I said in another comment, plus the caveat:

This logic also assumes you’re getting over as much as you can (even totally off the road if it isn’t a ditch) whenever you see oncoming traffic though. Either way, not preferred.

I mention safety devices because obviously I think people should have them. There should be free/cheap options (or already on the bike when bought). A mirror should fix the desire to be going the wrong way, but even a bell used (her or you) could've improved the situation either way.