It's not crazy to argue for the combination of a lower alcohol excise tax and a minimum per-unit price for alcohol if harm-causing drinkers disproportionately choose the cheapest plonk while moderate drinkers choose more expensive drinks. The anti-alcohol lobby likes to point out that moderate drinkers on average choose more expensive beverages, but this really doesn't tell us anything without a correction for income - if heavy drinkers disproportionately come from poorer cohorts, and if poorer people of all drinking intensities choose cheaper products, then income cohort effects confound things.
Consider though the Lindauer Rose, a bubbly that often retails around the $9 mark. It's 12% alcohol, so it's around 7 standard drinks. Labour's preferred $1.50 or $2 per standard drink minimum price would bind on the Lindauer Rose. Cheap plonk consumed by harmful drinkers? Or an Air New Zealand Wine Awards Gold Medal winner?
If the cheaper alcohol categories include nicer drops very plausibly chosen by moderate drinkers on a budget (or even ones at which I'd turn up my nose, so long as preference heterogeneity is allowed), we really really need to worry about harms imposed on moderate drinkers when weighing the effects of minimum pricing on harmful drinking.