I clicked that I was the rejected one, though I have also ended friendships.
But every time I've ended a friendship, there has been communication and I told the person why it wasn't working for me and gave them the opportunity to tell me if they saw things differently or if I was being unfair.
So that doesn't seem like suddenly and inexplicably cutting off all contact, to me.
However, both times I've had friends cut me off, there was no hint that things were going bad or that the he and she were unhappy with me or had problems I could do anything about.
In fact, the lesbian friend who did it to me had done it to others while I knew her, so when she did it to me, I knew it was part of her pattern.
The gay man who did it to me had been friends with a couple of people he was no longer friends with, and there were holes in the story about why they no longer communicated.
After he cut me off, it began to make sense to me that the situation with those other people was similar to my situation. He had simply chosen to cut them off at some point and had no good reason to do so, and therefore when he mentioned them, it never added up why they had been very close and then suddenly out of his life with no possibility even for a short hello on the street.
So, about OP's premise that we must be omitting information and there's more to the story than we're telling, I wish that were true and I could look at my behavior and find something I had done that I could examine or apologize for.
In both cases they were people I cared about deeply, and I would have loved to do some soul-searching and self-improvement in order to save those relationships.
Truthfully, though, as far as I can figure out, both of them had the habit of waking up one day and deciding they were tired of a friendship and were going to end it in a cowardly way, expecting me (and others, every time they felt this way) to go through weeks or months of trying to figure out what the hell happened.
I've felt that way about short-term bfs, but even then I generally have the decency to tell the guy it isn't working for me and I don't want to see him again.
The only times I've been so cold as to just not return someone's calls and expect him to get the hint is when we had only hooked up once or twice and there was no real investment on either side yet.