The problem isn't that they are waiting for conclusive information -but that they pick "both sides" out of moral cowardliness. When people accuse them of "both sides" it's cowardice that they're being accused of.
Cowardice aside, Centrists and Moderates are not people who are sitting on the sidelines carefully weighing the issues.
Far from it!
It would be useful to do some reading on who and what "Centrists" really are about:
https://fivethirtyeight.com/features/the-moderate-middle-is-...
https://novaramedia.com/2019/12/11/the-centrist-delusion-mid...
https://www.vox.com/2014/7/8/5878293/lets-stop-using-the-wor...
While it is appealing to believe that moderates/centrists really did look at all available data and came to a principled conclusion from first principles, I somehow doubt that that is the case.