You need to understand that you cannot finish objectives without winning fights. And you cannot win fights without damage.
You can have a great objective-oriented teamplay, but if you cannot kill that flag carrier due to low damage, you lose.
If your flag carrier dies in the middle of WSG without support, because half of your team is dead at GY due to low dmg, you lose.
If you try to cap a flag at Blacksmith in AB, but you cannot kill those 3 defenders, you will not cap it and you lose.
If the enemy assaults your bunker in AV, but you cannot kill the defenders and they burn it, you lose.
Do I need to continue?
Of course, the most successful team would have best of both worlds. Great damage and coordinated objective-oriented play. But it just does not happen that often. However, everything else equal, the team with better damage (and healing!) usually wins.
We also need to talk about the goals of various players that enter BGs. Some people just want to have fun and see some big numbers. And let's be honest, there's nothing wrong about that. It's not always about winning the BG. Even lost BG can be tons of fun. If you really care about winning each game, then maybe you should organize some premades or try Rated Battlegrounds.