I doubt that lighter pellets are inherently damaging to a springer. The real issue is the gun's efficiency at transferring energy to a particular projectile.
Guns store energy. Some of that energy drives the pellet, the rest is dissipated via friction, piston impact and spring vibration. If the pellet doesn't absorb enough energy, then the remaining energy can theoretically harm the gun.
In most springers, a light pellet will exit the barrel with approximately the same kinetic energy as a heavy pellet. It just has a higher velocity. This tells you that the gun's efficiency is roughly the same, regardless of the pellet weight.
Ironically, my .22 HW95 delivers the highest muzzle energy with the ultra light 9.56 grain FTT green, over 18 foot pounds.
However, shooting a felt cleaning punching through the barrel is an entirely different proposition. I did that once, then realized it was probably not a good idea.
