This is nonsense.
There’s no value in pitting one base vs another. Vote for/against the EBA on its merits.
Once upon a time it was basically all Sydney, now it’s much better. With a more de-centralised base system it affords the choice of any of the 5 major cities for pilots to live in and it’s easier on the home/family life to be close to their city of origin if they wish. There’s a lot of untold value in that and it’ll reduce stress and anxiety amongst the group as well. All pilots have had to move multiple times in their career but the fact that most can now reside in their place of origin is a good thing, and should be upheld, regardless of effects on density etc.