This discussion is pointless and unhelpful.
1) The decision has been taken, it cannot be untaken.
2) There is more than sufficient reason to cancel because the meeting cannot be productive
3) Holding the meeting would almost certainly lead to spreading the disease further
4) There is a significant probability that many attendees would be unable to return home if they attempted to attend.
5) It is very probable that the Canadian or US authorities will bar travel before or during the meeting.
Besides the public health concerns, we are about to see a recession the only question is how deep and how long. Many people's employers are going to be continuing to limit travel for the rest of the year. For most IETF participants, to go to Vancouver for an international meeting would have been a severely career limiting move.
Sure, we could ignore government orders. But these are orders that are being made to protect public health. The IETF is not an anarchist collective.
If folk were following my FB feed, they would know that two of the exhibitors at RSA have come down with COVID, one is on a ventilator. Had IETF 107 not been cancelled when it was, I would have begun a campaign on and off the IETF list to cancel. If it wasn't for the fact I am not fully coherent yet and can't actually attend anyway, I would have likely begun earlier.
