One of the principal ideas behind structural design is to distribute the load so that a ceiling or roof doesn't collapse. There is still weight acting on that beam, and we have 'engineering disasters' all the time in which a load bearing wall is insufficient to the task, and something collapses.

Typically, supporting a weight is less difficult than lifting it because less stress is placed on smaller stabilization muscles and more of the load is supported by skeletal structure, but there's still a huge strength component to it.