Here is some quick evidence: we live in a free world ruled by humans, not aliens. You have never seen an alien subyugate any of us, even if they could. They are here since long ago, and they have proven to us they intend no harm, by being in peace among us all this time. They deactive nuclear missiles, and that's pretty much how much they allow themselvs to "intervene", they are bening and wonderfull creatures, like us, full of love.