I hate Venom because I've always found him awkward to use, and since the first time I ever played through the game was with Millia, the personality hatred towards Venom just sorta trickled down. Some of the same is probably true with Eddie. The story mode just makes me hate their personalities totally, pretty much all because I picked Millia first.
I've never played Zato-1 though, because I started with GGXX, where he's turned fully into Eddie. All he does now is scream how he needs a body and scream incoherently the rest of the time.