Stupidity: Shriek is being taken to a new facility for superbeings, after a medical exam established that her sonic powers that she has been using since she was a kid are too strong to keep her at the correction house. So "naturally" for this transport she is not gagged, sedated, not even bound, and there's just one guy with her, not even wearing earplugs. It couldn't possibly be any more comically unsafe.
Stupidity: Kasady is the highest profile criminal in California; Eddie's symbiote reaches out for him in a very conspicuous way, tossing him around for the whole length of the cell in a thick tentacle shape, but that has zero consequence, implying that there's no sort of security camera in San Quentin. The guard in the room is not even directly behind Eddie, so he would have seen the large tentacle the moment he looked. (00:27:30)
Stupidity: Shriek aka Frances Barrison was taken away from the first mental facility when she was a teenager, having grown up there. She then spent the rest of her life, over 20 years, inside what basically was a cubicle of plexiglass. Despite that, the moment she is free she can stick drive like a pro. The way her life was presented, she shouldn't even know how to drive. (00:52:50)
Stupidity: Venom is sensitive to sounds (the first movie mentioned frequencies from 4,000 to 6,000 hertz, but in this movie both him and Carnage are utterly discombobulated by things like bells and alarms, to the point that if only the prison didn't have literally one alarm siren Carnage would have had a harder time escaping). So naturally he goes to hang out...at a concert. At the end of his soapbox speech he even literally drops the mic, causing a high-pitched Larsen that fails to get any reaction. (00:47:20)
Stupidity: Throughout the whole movie, wanton murderer Cletus Kasady and Shriek both spend an inordinate amount of time "almost" killing people, since they take forever to deal with them even having them completely at their mercy. Kasady even grabs Anne, tells Venom "You're gonna watch her die" and...leaves, to go eat her on top of the tower where Venom in theory would never see.
Stupidity: Kasady and Shriek set free Anne's husband, so he'd phone Eddie telling them about the 'wedding'. But they have as hostage Anne and the detective, and both have Eddie's phone number already. Talk about convoluted. Also, Eddie of course has his own phone and the police never thinks to trace him thanks to that. (01:06:35)
Stupidity: Thanks to Carnage, Kasady steals a car and clothes amongst other things. He then talks to his symbiote, acknowledging its existence. But that scene happens the evening after the night of his escape. The fact that he could have been on the run a whole day with no clothes and no getaway vehicle and without addressing the creature that allowed him to escape appears simply impossible (and it's just confusing editing due to Eddie's timeline with an extra day spent fixing his flat).
