Does the Marvel Universe public realize that Sinister Spider-Man is a different person than Amazing Spider-Man?
honestly, I'm not sure.
Either way, is any reason given why they love Sinister Spider-Man so much, when his appearance is basically identical to that of known supervillain Venom?
I think it's because he's sponsored by Osborn and anyone backed by Osborn is aces as far as the public is concerned.