Just recently they were shouting that they'll proceed with the conference[1]. Seen too many of those who were just few weeks ago advocating that COVID-19 is not a threat and it will be BAU. Finally everyone stopped ignoring and taking it seriously.
So they had to act as if everything was going ahead as normal while also hoping and planning for any contingency that would allow them to cancel the event without suffering financial ruin.
Did you read the March 12th blog post? https://pycon.blogspot.com/2020/03/march-12-update-on-covid-...