It's a very decent theory, but don't confuse someone agreeing that spending money to reduce environmental lead is a good bet (where the standard of proof is not extremely strict, and that's a good thing) with someone saying that "lead causes crime."

Just because Kevin Drum likes it doesn't make it "widely accepted." You oversell his theory. It's proven about as well as abortion reducing crime, which has good evidence behind it but is hardly a slam-dunk case.