I suppose it 'should be' the way you state it, but that's if you want the most neutral way of saying it. You can move a relative clause to the right of its normal position for stylistic effect -- or if it is too long to be easily grasped in the normal position.
(EX1-a) [Decisions [that cannot be unmade] have been made by omission, neglect, inertia]. (Ex1-b) [Decisions have been made by omission, neglect, inertia] [that cannot be unmade]
As JC said, people often move an adjective that-clause to avoid too long/heavy constituents at the head or in middle of sentences. Linguists call this kind of rightward mo