The author ends his post by stating that the rise of crime from the 60s through the 80s is a major puzzle (to him, in 2010 when he wrote it). I don't see this a

The author ends his post by stating that the rise of crime from the 60s through the 80s is a major puzzle (to him, in 2010 when he wrote it). I don't see this as an argument against the lead hypothesis in any way. Re: your second point, one of the three studies in the parent article looks at city level crime in the 1920s/30s using city piping infrastructure (lead vs. iron) for test/control groups. The leaded fuel was a substantial source of increased lead levels but not the only one.