Some of my «fans» responded...
1: «That's exactly what an alien would say!»
2: «You're an alien-denier!» (Taken from the same book as calling others a holocaust-denier)
3: «The greatest trick that aliens ever pulled was convincing humans that aliens don't exist»
(Okay... number three was actually mine...; the alien-denier then responded that it was the other way around that the greatest trick ever pulled by aliens was that they exist... which is kind of ironic)
4: «That guy (alien-denier) is being a heretic! Ban him already!»
5: «Only an alien who's trying to trying to deny/hide the existence of aliens would say that...»
And what-ever else we said during that «discussion» of sorts... because... aliens...!

They don't exist within the limited perception of most people.