To answer my own question, I think it is indeed! Just think about how easy it is to hit a target with any other weapon, whether be it a pistol, rifle, bow or x-bow. The principle is always the same, you have a target a shooting device and a some kind of sight, be it iron sight, red/green dot, scope, laser, or whatever.
While you still have a target and a shooting device, a "normal" slingshot doesn't have any real sight. What you have is A LOT of guessing (ammo weight, flightpath, wind, up- or downwards angle) but most of all it is about INSTINCT and your experience when it is right to to that shot, it is actually never really about aiming....
In my opinion slingshooting has a lot to do with "freeing your mind" I'd like to refer to the outstanding movie THE MATRIX (part 1) to the famous scene when Neo visits the oracle and in the anteroom kids doing funny things with just the power of their minds and one kid tells Neo that there is no spoon. Now don't laugh at me but when you follow this "no spoon theory" and you kind of free your mind (I can't hit that target because it is too small, too far away, too high, too low....etc) and you just tell yourself that you CAN and WILL do that shot and really FOCUS on the target it might work exceptionally well (but takes practice and self discipline). I found for me, that this "no spoon theory" will work great, admittedly not always but more often than not and this is amazing I think. Just yesterday I managed to do succesfully a rather difficult shot with that method. Target is about 25x18 cm and was approx. 80 meters (measured by foodsteps) away.
So, my conclusion is, that slingshooting is truly an art form. If you can hit with a slingshot, you can hit with anything, let me know what you think about it, I hope for an interesting discussion...
cheers