The public of New Zealand are calling out to the government to pull the troops out of Afghanistan. They some how get in their heads that the NZ SAS don't want to be in Afghanistan. If they didn't want to go, they wouldn't join the army. Many of the troops are in fact almost asking to go and help. The unwritten purpose of an army, is to kill people. Although that may sound harsh, it's true.
Besides some of the New Zealand deaths in Afghanistan don't even count as war casualties. Other New Zealand soldiers have died when their trucks rolled when they were not under attack.
And finally having NZ in Afghanistan is important for country relations and trade. Since declaring ourselves nuclear free, the USA has disliked us because they can not bring their war ships into our waters. Being part of the Afghanistan effort puts us back up there with Australia.