Would anybody with even an ounce of critical thinking faculty believe this even if they explicitly came out and said "yep, we've got aliums, folks"? There's literally no level of evidence I would accept because the premise is contrary to numerous, basic logical inferences.
How is it fundamentally illogical? I mean I'm skeptical as hell, but one possible answer to the Fermi paradox is that there is no paradox because there are aliens here.
Sit back and enjoy the ride.