It's a combination of virtue signaling/perceiving the risk to be higher than others perceive it to be (right or wrong; not commenting on the merits), and the long lead times/limited financial reserves the org has in planning events.

The go/no go decision had to be made months before, and there was some risk of covid restrictions being in place in December which would have made the event suck or not happen. Probably harder to cancel a single event in, say, 2019 over that level of risk, but easier to continue not running it in 2020, 2021, and then in 2022, I think. I really hope it happens this year.