Again the big difference is in MOS 17, there's really no arguing that those were not Doomsday fists. However, in Web 18, those hands are just too ordinary looking and there's no other supporting evidence that they belong to Eddie Brock / Venom. I know what you mean that it would make sense that they should belong to Venom, but what's stopping a writer from making a new villain tomorrow that knows Spider-Man's secret identity and can evade his spider sense? If that writer decides to reference back to Web 18 stating that this character has always been stalking or trying to kill him, that will throw a wrench to all the folks that bought the book thinking it was Venom. I'm not saying its not Eddie's Brocks hands nor can anyone officially say it belongs to him. It's just too vague to be considered a key.
Not even Marvel?
WOW. That's some direct evidence if I have ever seen it. The only reason the market won't relfect this is because the knowledge isn't well known. Here is some more:
In this image Peter's leg is grabbed by what appears to be venom.
and then Pete connects the events from issue 18 to 24.
So if the argument for MOS 17 over Web 18 is simply that the hand isn't Venom then issue 24 appears to take care of that.
Unequivocal. This is not "ret-con" it's contemporaneous and intended.