Part of it is because Itch groups discussions per project and not per creator. So if someone doesn't follow all of a creator's works, it's easy to assume that no status update in a particular project = creator has quit/died/been abducted by aliens.
As for me, I always assume abducted by aliens. A few months later, the creator usually pops up again, and that makes for a far more entertaining explanation than working on other projects.