Fidelity on the register - good sign, page-29

well I just learnt something! thx
that explains why I have watched big trades go thru in an instant, and I wonder where the orders suddenly came from, because I never saw the Buys on the screen.
I just thought it was someone very quick on the Buy/Sell button, but in fact they were probably sitting there all along, hidden from us mug punters.

I am confused - the whole ethos, business model of the ASX is supposed to be all about equality, openness and transparency.
yet we have these "dark pools", these hidden orders, and these Computerised traders who place their computers literally next to the ASX computers.
So how is it a fair marketplace?