[quote=Lilo...Would it change your mind if you thought that Fredo was more stupid than malevolent?...[/quote]

Of course not, because we already know he was stupid that's how he got snookered in by Ola & Roth.

Fredo's resentment toward Michael was understandable...but his stupidity led him to act upon that resentment. That's what made him dangerous, and what may have made him dangerous again in the years to come. He had to go.