What does that have to do with his batting ability? Is there something magic about the area between first and second base that sucks your hitting powers away? Rogers Hornsby played 2B, and he had 500 more RBIs than Ryno, with 200 fewer at-bats.
If you want to play that game, Ted Williams had more homers than Ernie Banks and had 1700 fewer at bats. By your reasoning then, Banks shouldn't be in the Hall either.
Like it or not, Sandberg was one of the best at his position at batting and fielding. That is why he went to the Hall of Fame. If you deny Sandberg, you must also deny Joe Morgan.
If Sandberg gets you frosted up, take a look at Bill Mazeroski's numbers.
General, Ernie Banks started out as a shortstop and then switched to first base. Ernie was a career 275 hitter who had pretty good power. But he wasn't in Sandbergs class in the field and Sandberg hit 10 or 12 points higher over his career. They both belong in the Hall of Fame.