Not necessarily. It's an easy way of ignoring the people that aren't part of your group though.
The fact is that each party in a political party has policies aligned towards a particular group, as long as that group makes up a majority of the people. In the US the parties are somewhat divided across wealth distributions but there are many more axes that may align better with certain policies and people are the intersection of all those.
Democrats policies align well with those on or near welfare (expansion of it) and the ultra-rich (since they are benefiting by limiting trade through increased taxes on the middle class and government-approved/sponsored corporations).
On the other hand, Republicans have policies geared towards the middle class; reduction of taxes and free trade benefit small and medium sized corporations but this also includes the lower educated (manufacturing and starting businesses doesn't take a PhD).
It doesn't mean that Republicans are dumb and Democrats are poor, as a result of their policies part of their base makes up that demographic but it's by no means the entire party.