At one of the least important defensive positions on the field. A gold glove in right field is worth less than a gold glove at many other positions.
True, but a rightfielder's arm is more important than the other outfielders' arms and Ichiro certainly has that. He's arguably the greatest defensive rightfielder ever (well in the AL). Only Roberto Clemente has had more gold gloves at the position and Willie Mays is the only other outfielder with more gold gloves.
Keep in mind that the MLB does not give gold gloves by specific position in the outfield. The voters decided he was one of the top three defensive outfielders in the AL for 10 years.
But keep in mind also that the Gold Glove doesn't always come even close to rewarding the best players and is basically the best defender among name offensive players (of course Ichiro playing an offense plus position that means it is more meritorious than say Jeter winning all the time). But it really isn't close defensively between Mays and Ichiro given that Mays played in bigger parks and had the bigger responsibilities (the Polo Grounds were nuts). I know you know this but my main point bringing it up is that while Centerfield is a lower value defensive position than the infield minus first his defensive value was incredible.