Spread the word, it might actually get some of your teammates to help capture a point or two. Sure it's not true but any little bit to tip others into play the objective in an 'objective' based mode helps. It's like the majority of players think you'll get infected with some crazy virus if you try to help capturing a point.
The problem is that too many Destiny players care about their precious k/d that they're unwilling to do anything that could potentially lower it. Your k/d ratio seems to be a badge of honor in the Destiny PvP community. I remember about a year ago someone in a comp match refused to defuse a bomb when he was the last one standing on our team. We could have potentially won the round, but he was just being an idiot by running away instead. After the match I asked him why he sabotaged our game, and he said he didn't want to risk it blowing up because it would lower his k/d... ARE YOU -blam!-ING SERIOUS? People will do [b]anything[/b] to increase their k/d ratio. I'm not surprised people won't capture points in Iron Banner.