An umpire could have legitimately called that a throw and awarded a free kick against. The AFL umpiring department would have, with earnestness and straight face, explained why the umpire would have been correct.
In this case, given that it will be the goal of the year they will, with due earnestness and straight face, explain why it wasn't a throw.
Its all to do with the marketing.
Which is why, in due course, the playing time per quarter will be shorter to enable commercial broadcasters to control the total duration of their broadcasts without sacrificing advertising time. That said, shorter quarters v Hawthorn might have been a blessing!