I never took the fans to task for rooting for a Japanese player. It is based in racism, but as you have pointed out it is not harmful or evil racism. However, to give a player employment using race as a motivation is immoral and often illegal.
No, you entered it into the discussion by inappropriately suggesting that Mariner ownership would desire having Dice K on the team because he is Japanese. You can argue that your statement was not rooted in racism and that you were referring to nationality, but your statement is no less offensive. Discrimination in employment based on race, ethnicity or "national origin" is illegal. You can tap dance around this as often as you like, but in your fervor to land King Felix you were promoting an illegal employment practice. Some would call it a racist practice. I don't think you are a racist in the least, but even if your intent was benign, you were inadvertently promoting an illegal employment practice.
I really would hope that the management of a team that I root for would make personnel decisions based solely on performance with the intent of improving the team and not because a player is Japanese or Mexican or whatever.