Since the Bible is considered historically accurate in general even if scholars quibble endlessly over most of the minutiae, I figured this belongs here than in the fictional lolcow section:
http://gethn7.blogspot.com/2017/03/top-five-dumbest-people-in-bible.html
I'll summarize for those who want the short version:
5. Nabal, guy who went out of his way to piss off David, a highly skilled mercenary leader, and a lot of guys with a lot of pointy weapons, and did it for the dumbest reason ever. He died, and everything he had wound up David's anyway.
4. Uzziah, a king who did everything God ever wanted for decades, then made one stupid mistake that made him point and laugh worthy to the point it basically undid all the good he ever did. Got crippling leprosy and died in agony because he decided he could do something everyone knew wasn't allowed for him to do, but tried to do it anyway.
3. Ahab, a king who had occasional moments of doing the smart thing, but immediately doubled down on being a dumbass every time to the point he earned the moniker of "Israel's very worst king".
2. Jeroboam, a man literally handed over 80 percent of the Kingdom of David for free from God, then immediately set about flipping God off for the rest of his life, even though he knew doing so was a really stupid idea.
1. Rehoboam, the dumbass responsible for making Jeroboam taking most of his kingdom away by being such a retard it was basically inevitable, mostly because he was given the choice to ease off on being a dick or most of his kingdom would defect, and he chose the stupid option despite tons of warning about the consequences.