Not sure what intelligence has to do with ridiculousness?
Remember, Lex is the same person who created a special super computer to find out Supermans identity.
The computer goes "yeah, dude's Clark Kent".
Lex is all "f*ck it, he can't be Superman!". Cuz the guy could not even comprehend the fact that Superman did anything with his time other than chill in the fortress and fight super villains. Despite the fact being a reporter would be the perfect cover for Superman.
__________________ Chicken Boo, what's the matter with you? You don't act like the other chickens do. You wear a disguise to look like human guys, but you're not a man you're a Chicken Boo.
Breaking news: Trump demands Superman and all illegal aliens leave the USA immediately and never return.
*24 hours later*
Breaking news: Metropolis and most of the US have been utterly devastated by evil super villains. President Trump tweeted from a secret underground bunker the super villains were all in the country illegally.
__________________ Chicken Boo, what's the matter with you? You don't act like the other chickens do. You wear a disguise to look like human guys, but you're not a man you're a Chicken Boo.