Ben would not have just let him go. Ben would want Peter to forgive him but he would also want Peter to try and convince Marko to turn himself in. He would not want him to just let him go.
"With Great Power comes Great Responsibility" doesn't just apply to Peter.
Sandman has great power. He chose not to use that power responsibly.
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I guess "With Great Power comes Great Responsibility" only applies to Peter then?
Sandman isn't dangerous? He was willing to kill Spider-Man. If he hadn't been helping Venom...Harry would still be alive. Peter only went to Harry for help because he couldn't fight them both alone.
Venom didn't threaten Marko's kid. He just said "Together we can kill Spider-Man" and Sandman was in.