Haven't read six pages of repeats, but for those who question why some would suggest starting with a .22, it really is simple. For some of us, the s...t.s and giggles of shooting is delivering a projectile on the desired location of the desired target. Some of us like to get to the s...ts and giggles quickly, with minimum fuss and deviation - for which read frustration.
It is simply easier to learn the nuances of accurate shooting when you have absolutely minimum blast, recoil and cost. While dry practice is useful, live fire validates that dry practice. Live fire with a .22 is much less expensive, and therefore much more likely to happen.
Even with a locker full of center fire handguns, practice with an accuarate .22 points out any flaws in technique much more readily than will shooting a center fire.
Regardless of the game you eventually play with your gun - be it IPSC, plinking, silhouette, IDPA, - none of these are fun if you ain't getting hits. You only win any of these games getting good hits. Old Bill Jordan of the U S Border Patrol said "You can't miss fast enough to win a gunfight." You can't win much of anything with misses.
Yup, you can learn to shoot starting with a .45. DND starts 'em with 9's. Cadets use a .22 though, and if you see an ex-Cadet on the rifle range, he can normally hit his target with most any rifle you give him. More than I can say for most of the folks at the range.