We're told Doctor Strange's botched spell accidentally summons into this universe the villains from elsewhere in the multiverse who know that Peter Parker is Spider-Man. But, of course, that qualification begs the question: how does Electro get caught up in the spell? Electro, one of the villains of The Amazing Spider-Man 2, never actually sees Andrew Garfield's Spider-Man unmasked.
No Way Home even doubles down on this by having Electro joke about how he always hoped Spider-Man was Black. While it's a fun reference to the Miles Morales version of Spider-Man most recently seen in the animated Into the Spider-Verse universe, it highlights that Electro didn't know Spider-Man's identity, so he never should have been affected up by Strange's spell in the first place.