How did people millennia later react to the strange artifacts found in the area of Harappan Civilization?

They ignored their significance.

In addition to exploring the facets of the Harappan civilization through the analysis of material remains, it is important to consider the story of how archaeologists came to "discover" this ancient civilization. Over time, as Harappan cities fell into ruins, knowledge and awareness of their existence faded away. Millennia later, when people began inhabiting the region, they encountered unfamiliar artifacts that surfaced during floods, soil erosion, or were accidentally unearthed while farming or searching for valuables. These encounters sparked curiosity and eventually led to the realization that these artifacts were remnants of a lost civilization, triggering the journey of archaeological discovery.