Basically the same answer as above.
The muzzle energy isn't the problem since most "magnum" springers are running something less than 20 ft*lb and a rim fire is on the order of 100. Heck, a 223 is around 1000 and a .30-06 is on the order of 3000. So it isn't just based on the energy level, but the frequency.
When a high power rifle goes off, the pulse amplitude is much higher than a spring gun, but the width of that rifle pulse is on the order of 1 to 2 milliseconds. When a spring gun goes off, the acceleration goes one way and then the other, but it isn't the amplitude that is the problem, it is the width of that pulse. Each one is on the order of 50 milliseconds or more, in two directions.
So, think of it as the area under the curve. Because the frequency is so low, the area under that curve is huge, and mechanical parts can start reacting to that frequency. With high power guns, that shock pulse is too high of a frequency and most parts can't respond to this.
The spring guns move a mass forward that rams an air column to the point where the piston actually bounces or slows before the air pressure causes the pellet to move forward. Then the volume of air starts draining down the bbl. As all that piston and spring mass accelerates, and those are heavy mechanical parts, so can all the internal mechanical spring loaded parts inside your scope. Those are all on a similar frequency since they are spring mass parts too.
When gunpowder gasses expand, they do it much faster than airgun parts, so most of that action is too fast for the parts inside your scope to respond.