An endless debate. Each person makes their own choices. Competance, experience, confidence, and what is at hand are all important. No one tool does everything well - and pistol is just a tool. Just as your weight example has merit if that is the sole measure of effectiveness, there are other arguements that use other measures.

As an aside, I have legally taken much small game with +P+ 45 Colt handloads that edge out 44 mag energies and find it significantly easier than with a 22rf pistol - without "damage" to the meat. There's not a significant amount of velocity difference between a 22lr and common centerfire pistol calibers (in fact, the 22 lr family has some offerings that are zippier than most). Neither has "explosive" effects on small game - that's mostly a function of velocity, and pistols are way under that threshold, even at the muzzle. The other main variables are resistance (small animals offer nil), proportion (sparrow vs rabbit vs caliber), and to a tiny extent in small game, bullet construction. A hard cast bullet or anthing jacketed is not even aware of passing thru small game.

But I don't see anything wrong with a 22 pistol and if that's where your thinking carries you, have at it - it's not a bad choice, just a choice. "If only one..." inherently carries compromise. You make a point - and there are other points - weight them (no pun intended) as you see fit for yourself.

Regards,

Tom