Fun fact:

Something similar happened in a 1987 comic. Lex Luthor used a machine to gather facts about Superman and the machine came to the conclusion that Clark Kent is Superman.

But Luthor simply rejects the idea, thinking the machine must have got it wrong because the idea is preposterous, and he as a person obviously knows better to distinguish between Superman and a mere human like Clark.

I imagine something similar would happen with Lois here, with her dismissing the facial recognition as an error.

damn lex for a super evil genius ur a fuckn moron

I attribute it more to just plain old arrogance and stubborn pride than anything.

It’s pure projection really. If Lex had the power of a Greek god, he would never pretend to be anything less. So he can’t imagine anybody pretending to be Clark fucking Kent if they had better options.

Even in the recent story arc where the world finds out Clark Kent is Superman, Lex still kind of refuses to believe it.