Just because one can do something doesn't mean that one should. When it comes to hunting we owe it to the animal that it be dispatched in as quick and humane way as possible.
Under perfect conditions a ,.22 can be just as effective as bigger rifles but in the outdoors, we rarely encounter perfect conditions. Pigs, with their natural armor and resilience deserve and demand better than a .22. I seriously question the ethics of anyone that would argue otherwise. Yes, I've head numerous stories of how a monster was stopped in its tracks with a .22, but I've also seem videos of hunts where pigs went unfound after a magazine dump.
I like pushing myself and my equipment as much as anyone else, but not at the expense of another living creature.
Just my .02, take it as you will.