SPOILER - Problem with 'Meeting our makers'

StevenLyall
MemberOvomorphJune 07, 2012892 Views10 RepliesSPOILER - I haven't seen this discussed yet.
The movie viewer can assume that the 'Sacrifice Engineer' in the opening scene helped to 'make us', or at least to accelerate the process.
But the crew and all involved in the mission wouldn't have had that certainty at all. All they knew is that some cave drawings pointed to a place in space.
Awesome enough that they may find that 'we may not be alone', but what would have made them assume that the alleged visitors to ancient earth were our makers?
This evidence-free assumption seemed to suddenly become the focus of the mission.