That driver is obviously an idiot that needs his license revoked.

That said, as a fellow cyclist, you all need to do better as well. For this large an event, there should either be a road closure, or break it up into flights. If those aren’t feasible, restrict yourselves to one lane instead of taking up both. Not excusing the drivers carelessness at all, but judging from your reaction to other comments here, your ride group’s sense of entitlement is a problem as well.