What a Dud is Albanese, page-14

we don't need a religious discrimination bill allowing schools to sack teachers

I think it was about allowing faith based schools to give preference to people of their own faith when hiring staff.
Which seems reasonable. A teacher would need to share the values of the school to teach those values to students or live a lie.
What some of the Coalition at the time didn't like was allowing schools to discriminate against LGBTQIA+ students.
It seems a somewhat tricky situation to legislate.