The worker (anonymised as HGY) transitioned and legally changed his name in 2012.

...

The health district argued in the tribunal that the Former Name Check Condition was essential for roles involving work with children and young people.

The worker had already submitted a valid Working With Children Check. There was no legal need for his colleague to have access to that sensitive personal information.

That's why it was discriminatory. "New" name is legal (2012 is 14 years ago, that's not new) and work permit was already valid, plus the reason was complete bullshit.