Big seas are quite scary and very difficult to outrun or evade. The Sydney to Hobart yacht race is an immovable calendar event ...and a race as the name implies.
The CYCA has learnt a lot since the 1998 tragedy, so better for these crew to pull out if the conditions get too challenging and race again next year rather than press on and possibly never race again. These modern yachts are so finely tuned that even small equipment failures due to rough conditions will often render them uncompetitive.