The article is referring to "1987" due to a US Supreme Court decision Shaare Tefila Congregation v. Cobb 481 U.S. 615 (1987)
What this decision actually says is:
We agree with petitioners, however, that the Court of Appeals erred in holding that Jews cannot state a §1982 claim against other white defendants. That view rested on the notion that because Jews today are not thought to be members of a separate race, they cannot make out a claim of racial discrimination within the meaning of §1982. That construction of the section we have today rejected in Saint Francis College v. Al-Khazraji, ante, p. 604. Our opinion in that case observed that definitions of race when §1982 was passed were not the same as they are today, ante, at 609-613, and concluded that the section was "intended to protect from discrimination identifiable classes of persons who are subjected to intentional discrimination solely because of their ancestry or ethnic characteristics." Ante, at 613. As Saint Francis makes clear, the question before us is not whether Jews are considered to be a separate race by today's standards, but whether, at the time §1982 was adopted, Jews constituted a group of people that Congress intended to protect. It is evident from the legislative history of the section reviewed in Saint Francis College, a review that we need not repeat here, that Jews and Arabs were among the peoples then considered [481 U.S. 615, 618] to be distinct races and hence within the protection of the statute. Jews are not foreclosed from stating a cause of action against other members of what today is considered to be part of the Caucasian race.
So the decision was not that Jews were non-white in 1987, it was that at the time the law in question was created, Jews were thought of as a separate race.
The law in question originated 9 April 1866, so they are saying in 1866 Jews were considered a separate race.
The decision cites to Saint Francis College v. Al-Khazraji which was decided the same day and says:
Encyclopedias of the 19th century also described race in terms of ethnic groups, which is a narrower concept of race than petitioners urge. Encyclopedia Americana in 1858, for example, referred to various races such as Finns, vol. 5, p. 123, gypsies, 6 id. at 123, Basques, 1 id. at 602, and Hebrews, 6 id. at 209. The 1863 version of the New American Cyclopaedia divided the Arabs into a number of subsidiary races, vol. 1, p. 739; represented the Hebrews as of the Semitic race, 9 id. at 27, and identified numerous other groups as constituting races, including Swedes, 15 id. at 216, Norwegians, 12 id. at 410, Germans, 8 id. at 200, Greeks, 8 id. at 438, Finns, 7 id. at 513, Italians, 9 id. at 644-645 (referring to mixture of different races), Spanish, 14 id. at 804, Mongolians, 11 id. at 651, Russians, 14 id. at 226, and the like. The Ninth edition of the Encyclopedia Britannica also referred to Arabs, vol. 2, p. 245 (1878), Jews, 13 id. at 685 (1881), and other ethnic groups such as Germans, 10 id. at [p612] 473 (1879), Hungarians, 12 id. at 365 (1880), and Greeks, 11 id. at 83 (1880), as separate races.
These dictionary and encyclopedic sources are somewhat diverse, but it is clear that they do not support the claim that, for the purposes of § 1981, Arabs, Englishmen, Germans, and certain other ethnic groups are to be considered a single race.
So the Supreme court didn't mean that Jews were non-white even as of 1866, but instead that for the purpose of a particular law originating in 1866 there are many different races. Even Englishmen vs. Germans are different races for the purpose of this law.
For more information see SECTION 1982 AND DISCRIMINATION
AGAINST JEWS: SHAARE TEFILA
CONGREGA TION v. COBB