I think that what ever proof comes up alot of people will refuse to belive it.

The reason is religion.

Religious people will always find a way to mold the reality to fit their religious belifes.

If aliens made public contact religious people wuld say; we are all Gods children.

If the aliens went, Jesus who?

We would be the choosen people and that would be the explanation for alens not knowing of our God.

If the aliens showed us evidence for a creatorless reality the religious people would call them the great decivers and satan.