The Cavs didn't play defense because they don't have the personnel to do so.
Love actually improved quite a bit and he shifted his game a ton to try to meld into a roster with LBJ and Irving. He's really not getting enough credit for modifying his game to try to help his team win.
The Warriors backed down on defense late in this series because the refs were committed to trying to get all the key Warriors into foul trouble to try to extend this series. The Warriors have the personnel to play good defense, they are just such a well balanced team they soft pedal it because the refs have a soft whistle and beat you in 35 other ways.
The Cavs plowed through a weak East, and let's not kid ourselves, compared to the West, it's a much softer ride to the Finals. The Warriors got there by destroying everyone in their path. They would not have gotten there without their defense.
Defense does win championships.
Defense however cannot defeat 8 on 5 rigging sponsored by Nike and whatever brand car that Blake Griffin is dunking over right now.