Why were the ground wires in my light boxes either cut off or tucked away unused?

I live in a home built in 2006 in Delaware. There are a mixture of plastic and metal boxes for light fixtures throughout the house. I am in the process of replacing builder grade lights with better finishes.

Every single box I come to the ground wire for the fixture has been snipped to the base, and the ground wire from the cable is either curled up in the box or snipped back to the sheath cut. The metal boxes have ground screws with nothing attached to them, Is there a reason for this or is it just bad work / laziness? It literally takes 30 seconds to connect the two wires much shorter time than tucking and trimming them in my opinion.

I am by no means an electrician, just looking for some education on this subject. I only ask because the plumbing work done here was also shoddy, missing putty, unglued joints, overflow on tub not connected… a real winner lol. Thanks in advance!