That there was no condensation funnel means the tour is exempt from criticism? Not that I'm here to criticize, but this is not really a valid excuse because from your description it sounds like the tour van was operating underneath a tornado producing part of the storm, and then it was impacted by a tornado. Sure the winds may be on the low end for a tornado, but if it's a circulation doing damage, it sounds like a tornado to me.
Was the tour intentionally operating under a dangerous part of the storm, or were they dangerously unaware? It would be really insightful to see what went wrong here. I know many chasers compromise their own safety for the sake of getting a view, but I think many are going to be much more critical if a tour group is doing this.