I've not had a chance to look at the Chicago statutes/ordinances, but the requirement that a candidate be both a "qualified elector" and a "resident" for a defined period of time is a typical one imposed on candidacies, and the two qualifications are not necessarily surplusage.  In order to be an "elector," one must not only be a resident of the jurisdiction, but a citizen over a certain age.  In some jurisdictions, it also includes a requirement that one be a registered voter.

 

I also find it problematic that the court essentially found that the same word, "resident," had two different meanings in the two election statutes.  Typically, "residence" is a more inclusive concept than "domicile," not a less inclusive one.

 

As for the policy rationale, I don't see why the voters should not be deemed capable of deciding for themselves whether somewhat like Emmanuel is sufficiently in touch with the day-to-day problems of Chicago that they should want to vote for him or not.