Perhaps they are doing what they consider to be correct according to the information available to them. The question then becomes what information are they being given?
How are any of us supposed to vote in our best intetersts, individually or collectively, when all the bastard politicians are pathological liers.
Read history, read the news, read foreign news sources (since they have less of an incentive to lie to you about your own country's domestic policies), use your brain.
View through all the lenses at your disposal (there are many), apply critical thought and compare theory to fact. If you find your answers change from absolutes to 'it depends which perspective you start from' then you are probably on the right track.