What does it mean to say that the two major parties are more election-oriented than issue-oriented?

This basically is an assertion that the Democratic and Republican Parties are more concerned with winning elections than with making good policies.

When people choose a certain political affiliation, we often develop a tendency to be really biased and lashed out at every little things that other parties do.
Republican and Democratic parties often used this tendency to blatantly make policies that popular to a certain demographic while demonizing the other party, regardless what it caused to our unity.