>... what truly hurt me was that the words of this person were enough to turn an entire group of colleagues—and even some people who were becoming something closer to friends—against me. It hurt me professionally and it hurt me personally. Almost none of these people bothered to ask me if any of this was true or discuss it with me—they just ostracized me immediately.

If they ostracized you right from the get-go without even listening to your side of the story, then they obviously weren't friend material to start with.

>The few people who did not behave that way—I’ll be grateful to forever. They had integrity and honor. And at the very least, curiosity.

This could be considered a good result of such cancellation attempt: You got rid of heavy luggage you didn't know you were carrying, and ended up with a lighter and healthier weight.