Did you read the article linked in the OP?
The court ruled 5-4 that Ohio did not violate federal laws by purging voters who failed to vote for six years and did not confirm their residency. Ohio has the strictest such law in the nation.
The ruling protects similar laws in six states, including several electing governors or U.S. senators this fall. They are Pennsylvania, Georgia, Oregon, Oklahoma, West Virginia and Montana. Justice Samuel Alito noted in his majority opinion that about one in eight voter registrations in the USA are invalid or inaccurate. He said failing to vote cannot be the sole reason for purging voters, but Ohio "removes registrants only if they have failed to vote and have failed to respond to a notice."
Under federal laws enacted in 1993 and 2002, states cannot remove voters from registration lists because of their failure to vote. But they can do so if voters don't respond to confirmation notices.
"A state violates the failure-to-vote clause only if it removes registrants for no reason other than their failure to vote," Alito said. By contrast, he said, Ohio waits six years before removal, following federal law "to the letter."
https://www.usatoday.com/story/news/politics/2018/06/11/supreme-court-states-purge-voters-who-dont-vote/587316002/