The scientific review that he cites does not list poverty as a risk factor for dementia, but Picard is determined to add it by interpretation. 
"While things such as smoking and inactivity are commonly seen as lifestyle choices, they are largely symptoms of poor socioeconomic conditions." 
Really? What is there about poverty that necessitates smoking? Nothing! It's true that smoking is more prevalent in poor populations, but it is absolutely a choice. It's fine to be liberal-minded and empathetic, but it is irresponsible and rather condescending to deny people's agency and responsibility for personal choices. 
All of us should note the dementia prevention advice given here and do our best to follow it. No excuses.