I would disagree that the turbulence is the same regardless of the size of the aircraft. Several variables. I've flown in areas where 737s reported severe while I was in a light airplane and only found up and downdrafts but smooth conditions (moving too slow through it to get the jolt). Conversely, I've flown in places where I know it would be rough in a light airplane, but the heavy jet I was flying hardly was doing more than light.
As I've said before, if you like the stuff around PSP, you need to try the area around China Lake with a cold front approaching. It will make your PSP stuff seem like smooth air, and I've flown a lot in both regions!
I do think pilots tend to report it as rougher than it is fairly often. My favorite was one morning going into ANC. ANC approach was asking for ride reports as each aircraft got on base:
Alaska xxx how's the ride? "light chop"
FedEx xxx, hows the ride? "light chop"
Atlas xxx, how's the ride? "light chop"
Alaska xxx how's the ride? "light chop"
United xxx, how's the ride? "SEVERE TURBULENCE!!"
Alaska xx, how's the ride? "light chop"
FedEx xx, how's the ride? "light chop"
Above repeated, wtih those crews who obviously did not fly into ANC as often all reporting much worse turbulence than the experienced crews. It can get rough there, but you acclimate to it.