Beyond the phrase 'being backward'. It means lacking any
insight, intelligence, correct action, respect to
human rights, cultural
sophistication, and most of all common sense.
Having a parked car
on the lawn while drunk on a couch also on the lawn
ass backwards.
Being racist is ass backwards.
In the computer game Civilization having your nation in the dark ages when every other group is building spacecraft is being
completely ass backwards.
Putting something together wrong is ass backwards.