Two aircraft did as they were supposed to followed all the rules yet nearly collided.
I don't think it is correct to say that "all the rules" were "followed" in this case (although I'm again only going on the report).
As I read it:
- ZPJ on base to 09.
- XGA conducting a straight-in to 09.
- There is a clear rule specifying who has to give way to whom in that situation.
If that rule does not apply in circumstances that led to a "near collision" between an aircraft on base and an aircraft on a straight-in, the rule is meaningless.