This is retaliation for not selling a 50% stake in his catalogue to Sony Music recently. They want in before that biopic is released in theaters, which will surely cause his music sales to spike.
The executors of MJ's estate were for it, but his mother Katherine Jackson objected and has the deal tied up in court.
The major music publishers are going to get that catalogue away from the Jackson's one way or another. If his family fights, the media will continue to smear his name with these accusations and court cases. Very bad press in the Me Too era.
I suspect that if they sell, the focus on Michael Jackson's scandals will subside and revert back to his artistic legacy. Just a theory.