It has a bit to do both with the 1911 design, and the energies involved...
The 45, throwing 230 gr bullet, will generate more inherent recoil than a 124 gr out of a 9mm... There will be variances for load strength and velocities,, but we are looking at the general rule.. The 45 just kicks harder.. that's the brunt of it.
Also it may have something to do with the general design characteristics of the 1911 itself... The slide on a 45 has the bulk of the it's weight is at the rear, and when it is at full recoil position, the bulk of that mass is centered directly above the breaking point, or joint of your wrist... It has a tendency to make most everyone "Break" their wrist..
This is not as much an issue with revolvers, and not near as big an issue with most other autos simply because of the weights and energy involved..
The 45 Auto can generate up to 2000 G's in recoil.. that is a lot to handle when it is centered directly over or in the case of smaller hands, behind the fulcrum point. (the pivot point in the wrist)
It took me MANY years to learn to shoot a 45... I struggled with it for a long time.. I could write my name with a revolver, but a 45 gave me fits, I would on a good day drop 20 points + just by changing over to a 45...
An old 2600 bullseye shooter watched me one afternoon and said... "I can Fix that for you boy.." then he showed me how to grip a 45 where it naturally locked the tendons in my wrist... never had a problem since... I now hand onto every pistol in the same manner..
1st UNLOAD and make sure the pistol is in proper alignment with your body/Arm... that is there is a STRAIGHT LINE between the front sight and the center of your bent elbow... you can check this while gun is lowered by your side..
#2... don't grab the pistol like a baseball bat... take only the middle two fingers, between the pinky and the trigger finger, and use THEM to pull the pistol straight back into the palm of your hand. When done properly, there may even be a gap between the center of the palm of your hand and the right side of the grip (rt handed)
1st try gripping the pistol the way you always have, with a "Bear Claw death grip" or "Meat-hook Grip" as I have heard it termed, and look at the center of the wrist just behind the joint between your hand and arm.. and notice the shape of the muscle and tendon structure,, you will notice that they two major tendons that connect the arm and hand are not ridged... and if your not real skinny, probably not visible.
Now with the same old grip you have always used, Slap or hit the muzzle of the UNLOADED pistol. or with the off hand briskly rack the slide as hard and fast as you can.... notice that it will allow the wrist to break...or flex/bend...
Now, try the method described... the first change that you will notice... with the two middle fingers pulling the grip straight back into the base of the palm, is that the two tendons that connect your hand and arm at the wrist are now protruding..Two distinct straight lines either side of the centerline of your wrist..
Now slap or strike the muzzle. or a hard rack.. and notice that the wrist will not break with the impact.........nor will it with the recoil...
Keep your shoulders and elbow relaxed, and let shoulders and elbows ride the recoil, NOT your wrists... You will find that your recovery times are faster, and after you get your mind to ignore the blast, your on your way... Watch the scores come up...