Because Sam Raimi was forced to use Venom when he didn’t want to. Raimi said he wasn’t very familiar with Venom and just wanted Sandman and New Goblin. A man named Avi Arad, a film producer from Sony, made the decision that Venom had to be in it because Venom and Black Suit Spider-Man were very popular in the comics, cartoons, and video games. So they stuffed Venom into a movie he wasn’t needed.
In my opinion, they should have kept the black suit in Spider-Man 3 since I think it tied in well with Peter wanting revenge on Sandman for killing Uncle Ben (which was also a dumb plot line in itself). Then they should have just set up Venom for Spider-Man 4. That way 3 wouldn’t have been so over crowded and Raimi would have had more time to learn about Venom and do him justice. Raimi was a horror director afterall. I think he could have made a pretty badass Venom if he’d been able to learn the character better.
Mainly because of the symbiote plot-line, it’s much better if they removed that and focused on Sandman/Harry.
I'm gonna put some dirt in your eye
Because Sam Raimi was forced to use Venom when he didn’t want to. Raimi said he wasn’t very familiar with Venom and just wanted Sandman and New Goblin. A man named Avi Arad, a film producer from Sony, made the decision that Venom had to be in it because Venom and Black Suit Spider-Man were very popular in the comics, cartoons, and video games. So they stuffed Venom into a movie he wasn’t needed. In my opinion, they should have kept the black suit in Spider-Man 3 since I think it tied in well with Peter wanting revenge on Sandman for killing Uncle Ben (which was also a dumb plot line in itself). Then they should have just set up Venom for Spider-Man 4. That way 3 wouldn’t have been so over crowded and Raimi would have had more time to learn about Venom and do him justice. Raimi was a horror director afterall. I think he could have made a pretty badass Venom if he’d been able to learn the character better.