The reason for the current repatriation is primarily that Terendak is no longer a Commonwealth military base and hasn't been for some time - while Malaysia remains a member of the Commonwealth, Terendak is now solely a Malaysian base. Security considerations have made it difficult for Australians to visit the graves for some time - the Malaysians have done their best to be accommodating, but they have understandable and reasonable concerns about the security of allowing foreigners access to a base and that has made the process complicated. The relatively small number of remains involved, and the fact that many still have close family members still living, meant a decision was taken to repatriate these people to Australia if family members wanted it. A few chose to leave their loved ones in Terendak, but most accepted the offer.
There are some interesting photographs and more information at the linked article.
Great news that they are finally home at last.
Good God Almighty...what absolutely breathtaking *stupidity*! And *cruelty* for that matter!