Yep. Great post Monster.
At the beginning stages when you realize that the biggest component of a BH power shot is that your arm goes from bent to straight, and when you just put your racket out, you still put the ball on the table, then biomechanically, and technically, BH is easier to learn at that level.
If you are talking about touch and refining the shot to make more spin contact and on the bigger shots start adding more legs and waist, well, there is some extra to think about. But, it is still not as complex as all the moving parts of a FH: hips, legs, (are used much more on FH), upper arm, lower arm, wrist (need much more detail on FH and much more training to get your arm into a position that is "artificial" and hard to do, so that the blade face is adjusted for a SH FH loop). In PH, the racket position automatically goes to an excellent angle and position to spin the ball. In SH, you have to do things to your wrist and forearm to get the blade face close enough to spin well.
For SH BH, all you have to do is cock your wrist and it closes the blade face.
So:
1) Moving parts for basic mechanics:
a) BH = forearm (you don't need to think about the rest for the basics). The use of wrist is just very natural to a BH. You don't have to think about it for some use of wrist to simply fall into place. And the legs, hips, torso, they start doing what they should over time as a player improves.
b) FH = legs, hips waist, upper arm (stable), forearm; are all very important. And when you pass the basics, figuring out how to use the wrist is pretty complicated.
2) Angle of racket for topspin:
a) BH = very easy to use wrist flexion and forearm supination to close the racket on the BH side.
b) FH = without a big grip change it is very hard to change the angle of the racket so that the racket closes over the ball easily. The combination of wrist extension and forearm pronation which is needed is very unnatural to our arms. So many SH players with good FH have a noticeable FH grip.