Quite likely it's just something people like to hear, so it is being told to them. I vaguely recall that correlation between red wine consumption and longevity disappears if controlled for wealth. Can't find any links tho.
The red wine vs beer discrepancy could be down to wealth.
The drinker vs non-drinker could be down to the fact that seriously ill people fall into the non-drinker category.
Most people who drink mostly do so whilst getting together with friends.