Stupidity: When Bishop is first holding the gun on Gina in the cabin, he stands close enough for her to grab the gun and try to get it off him. A man of his experience would never make that mistake, it's one of the basic rules of controlling someone at gun point: Stand more than an arm's length away.
Stupidity: Given Enchantress' power, why not just try to cure Dr June Moone, so she can't threaten the world? That's what the government should've done.
Suggested correction: We're talking about Amanda Waller who had no issues murdering innocent government employees that were accidentally exposed to her top-secret Suicide Squad program they weren't cleared for (versus making them sign an NDA not to talk about it as in a real-life accidental exposure to uncleared employees). Waller just took the easier option which was to threaten to kill Enchantress if she didn't obey versus spending countless dollars (and exposing more people to Waller's program) trying to cure her.
Stupidity: Why does a safe house have a skylight? It is a secure building with hardened doors but a window in the roof?
Stupidity: The protagonists need to know what Pope is planning with his drug shipments, in secret. So they sneak under a false name into Pope's party and... the policewoman goes dancing with Pope, who knows her and that she is a police officer! Good that nobody asks her anything - she'd have no way to explain her presence! At no point it is even hinted that he was just about to go upstairs, why would he, after all, with all those guests? And their secret mission continues with the alarm being triggered and Ice Cube KTFOing guards. Some stealthy mission, and they are even captured at the end! And even after all these epic fails, they just assume that Pope is not going to change anything about the shipment details. And to make all of this even worse, they know about the port commissioner situation, they talk about it and how necessary it is for Pope to control the commissioner, but don't take half a second to mention his name, which is all it takes for AJ later in the movie to 'remember' that he's been bribed.
Stupidity: The Joneses forget to change their New York license plates to Georgia ones as part of their cover.