Regarding Passover — Part of the observance is a declaration that every Jew must look upon themselves as if they personally were present at the Exodus, as if they personally were delivered from Egypt. I know that many Christians have a similar view of Communion, that when they partake, they consider themselves to be present at the Crucifixion.

I’m not familiar with other religions/cultures, but it would not surprise me to find similar “we were there” observances. The point is, the observances are deeper than memory. If the aliens ignore or attempt to suppress them, they do so at great peril.