I think the argument is that, by and large, Australian football is no less violent than American football. However, helmets incentivise poor tackling technique

I think the argument is that, by and large, Australian football is no less violent than American football. However, helmets incentivise poor tackling technique (i.e. leading with the helmet). If you took off the facemask, the game would be just as quick/painful etc. but you wouldn't see defensive ends driving quarterbacks into the ground with their helmets... instead, they'd be wrapping up and tackling the way they did back in the day, before the "human bowling ball" approach became popular. EDIT: by the way, kids in peewee football are taught from day 1 to tackle with the head up. The "big hits" you see on ESPN are fundamentally poor tackles... they just seem to get the "oohs and ahss" because they look cool to people who don't understand football.