Unfortunately I do not have scans handy so bare with me as I try to explain this verbally. If you want skip to the last few paragraphs to find the question I’m actually asking.
We know of course that the Venom symbiote was aware that Peter Parker was Spider-Man. It then passed that information onto it’s host Eddie Brock as it and Brock wanted revenge on Spider-Man. Whether the symbiote actively told Brock this information or if Brock asked it to tell him is unknown.
Anyway in 1997 there was a one shot called Spider-Man: the Venom Agenda where Eddie Brock forgot who Spider-Man was due to a blow to his head.
In a follow up mini-series Venom the Finale Venom still doesn’t remember Spider-Man but another blow to the head restores his memory. At the end of the story the symbiote is separated from Brock and seemingly destroyed.
Later in Howard Mackie’s run on Spider-Man the symbiote tracks Peter to his new swanky apartment and tries to bond with him. failing that it seeks out Brock. Brock doesn’t know Spider-Man’s secret identity but he does remember Spider-Man ruined his career. The symbiote bonds with Brock and they become Venom again.
But weirdly Venom still does not know Spider-Man’s secret identity but remembers he USED to know.
Jumping forward in time we get to Marvel Knights Spider-Man by Mark Millar and Brock tells Angelo Fortunato (whom he’s sold the symbiote to) that the symbiote knows who Spider-Man is and will tell Angelo if he asks it nicely. He obviously does because Angelo then tracks Peter down to his high school reunion.
In addition to all of this in the clone saga Carnage found out who Spider-Man was due to the machinations of Judas Traveller although Traveller then erased this knowledge from his mind.
However later in the Clone Saga the carnage symbiote bonded with Ben Reilly and tried to tempt him into murdering Peter when the latter came by to visit him. At the end of the story the symbiote rejoined Cletus Kasady and from then on Kasady very obviously did not know WHO Ben Reilly or Peter Parker were.
So what I’m trying to resolve is why didn’t the Venom or Carnage symbiotes TELL Brock or Kasady who Spider-Man was? The Venom symbiote still hated Peter and knew who he was and Carnage knew from Ben Reilly.
There are a few possible explanations I’ve offhandedly thought of but I don’t know how much water any of them hold so input on them and the central question would be appreciated.
a) The Carnage symbiote didn’t say anything because it doesn’t hold any animosity towards Spider-Man the way Venom does and is more chaotic and animalistic anyway. So it maybe could’ve told Cletus who Spider-Man was but it didn’t care and Cletus never knew to ask.
b) SOMEHOW Brock’s amnesia prevented the symbiote from telling Brock who Spider-Man was, maybe because they shared a mind/body so the amnesia was sort of passed onto the symbiote whilst it was bonded to Brock.
c) The Venom symbiote had a weird love/hate relationship with Spider-Man and so maybe withheld that information from Brock because it wanted to kill him but had doubts, hence it didn’t make things too easy for Brock by simply telling him where to go to kill Peter in his sleep or anything.
We know in Mackie’s run after Venom was reborn it didn’t try to kill Spider-Man until it happened to stumble across the Sinister Six attacking him, and then afterwards switched his targets to the Sinister Six themselves and then to reconciling with Brock’s wife Anne Weying. So it wasn’t like Venom was trying too hard to kill Spidey. Later still in the Jenkins’ run of Spectacular Spider-Man the symbiote and Brock outright state the symbiote wants to bond with Peter not Brock. When Peter forced Brock and the symbiote to bond it had a big hate on for Spidey which would then explain why it was all too happy to tell Angelo Fortunato who Peter was.
d) By absorbing the Carnage symbiote into itself Venom simply became crazier and more erratic
e) The laziest explanation to hand is that the symbiotes being weird alien creatures have physiologies and psychologies that are simply different to how humans behave (not to mention Venom and Carnage are regarded as insane even by their own species) and so technically they can be entirely contradictory by human standards.
Thoughts
P.S. I don’t actually regard Brock regaining his memory as much of a plothole. If he got amnesia it’s not impossible to imagine his memory could come and go so him forgetting AGAIN makes sense