SIDS an STARS are there for tragic flow purposes
I think based on that it would be wisest to agree to disagree, we are unlikely to convince each other.
There's nothing logical about categorizing this incident as a LOSA.
If ASA Safety are calling it a LOSA then by definition there was no LOS, so what else would you call it?
"The controller messed up but by luck and/or pilot action three was no loss of separation" is just another definition of LOSA.
Unless you believe there was a LOS in which case you need to take it further and formally immediately, because there has either been a fundamental error in the investigation or a cover up.