Part of that's a translation problem. "Work" doesn't really express the same concept as melakha, which is more specifically human kinds of work than expenditure of brute force.
Over the years Rabbis have clarified and expand these definitions to understand how they relate to the current generation and modern world. This is a long conversation.
Ultimately, the general idea is "we create during the week and on sabbath, separate ourselves from that creative energy and just enjoy our handiwork, just as the creator of the world did... this is why even plucking a blade of grass would be forbidden..anything that creates either through adding or removing things is in the framework of how Shabbat laws are interpreted...
As I understand it in my lay background.