The elves are always there. The mushroom just lets us see them.

Humans are not supposed to know that yet. You'll get in trouble with management if you continue doing this.

Mnestics are pharmaceuticals that allow agents to maintain awareness of threats that otherwise erase themselves from human memory. The drugs are used to combat antimemetic entities by enhancing memory and enabling users to perceive or recall information that self-erases.

Finally a rational explanation.

William of Ockham confirms

They Live!