Appears that they did that because the State of New York is extremely lenient in allowing them to violate their own registration obligation in New York as attorneys, as a quid pro quo - an exchange of a favorable ruling for a lack of discipline against these judges who would not obey attorney registration rules in New York.
The majority opinion in Schoenefeld v Schneiderman of April 22, 2016 was written by two judges of the U.S. Court of Appeals for the 2nd Circuit:
Reena Raggi and Susan Carney.
Judge Susan L. Carney, according to the website of the U.S. Court of Appeals for the 2nd Circuit, is not licensed in New York State and, according to other sources, has graduated from the Harvard School of Law.
Judge Carney is reportedly married to journalist Lincoln Caplan who, quite "coincidentally", joined the editorial board of New York Times right around the time of his wife's nomination.
At the time of nomination, Susan Carney reportedly had "mediocre" ABA ratings, reportedly because of her "remarkable dearth of litigation experience".
So, this judge with "remarkable dearth of litigation experience" - who nevertheless was put on one of the highest benches in the country - decided to discriminate against out-of-state attorneys licensed in New York while having, apparently, no clue as to what litigation experience is and what burden she is imposing by requiring of a busy out-of-state attorney to channel his or her litigation through a physical office in New York, practically forcing that attorney to move into New York in order to maintain a law practice there.
Judge Reena Raggi of the 2nd Circuit U.S. Court of Appeals appointed in 2002 has the following attorney registration in New York:
The attorney registration rules in New York, which are to be enforceable against every attorney licensed in New York, dictate that whenever an attorney changes her employment, she must change her official registration information within 30 days.
Judge Reena Raggi assumed office in the 2nd Circuit Court of Appeals on October 4, 2002.
She had to re-register in New York, listing her changed place of employment, by November 3, 2002, within 30 days of "assuming office".
14 years later Judge Raggi still has her registration listing her as a judge of the Eastern District of New York, a BAD violation of attorney registration rules.
THIS is the judge who decided that discrimination of out-of-state attorneys licensed in New York is proper?
Because New York State does not enforce, as it should have, rules of registration that are equal for all attorneys - against the Judge, because the judge will then rule FOR the State of New York?
So, Judge Carney's nomination is promoted by New York Times despite mediocre ratings and no litigation experience because her husband joined the newspaper's editorial board at the time of her supposed nomination. And she got nominated.
Judge Raggi gets favors from New York in terms of non-enforcement of attorney discipline against her for failure to re-register for 14 years that is punishable for any other attorneys registered in New York - and Judge Raggi rules for the State of New York in return.