These people are dumb. The wealthy in Downton Abbey have pre-capitalist values. They revile modern American capitalism with its emphasis on meritocracy and relationships based on capitalist transactions. The inability of Lord Grantham to manage his money and his disdain for the self made newspaper magnate are both…

Pollsters balance their online samples so that they reflect the population in terms of age and other demographics. Online polling is pretty common and a well accepted methodology now. You could argue that old people who are online are different to old people who are not but that's not the same as skewing younger.