Why are Fake Survivors always the worst?

I've only come upon a couple "True Survivors" that actually felt like they made a difference in a difficult mission. Most though, are either painfully bad or just plain mean.

Like earlier, on an Auric Damnation Maelstrom mission, Smelter Complex, we get a True Survivor. At the very beginning things go bad from a series of bad events, me and my buddy are in the next arena waiting to be picked back up, and he's left behind a bot who goes down. He then goes back for the bot, which dies within the first few steps, so he keeps going back to pick a fight with the enemies. I say in chat to just keep pushing while things are calm, he says No. When he finally comes upon me and my bud, he initially goes to pick me back up, stops and pauses, before picking my friend up instead, Friend picked me back up after that. Throughout the mission he's just run ahead by himself, sprinting and sliding past enemies and monstrosities and even objectives. In one of the arenas, we get backed into a corner and he lets a Poxburster get past us and it downs me, so he runs over, tbags me, and then runs off. Minutes later he gets trapped by a Trapper after getting a solid warning, so I tbag him and run off. Rest of the mission goes by and he's literally no help, either rushing ahead or staying so far behind he'd be in the last arena doing god knows what.

Truly, he was a Survivor. Let your teammates die while he plays coward. A movie should be made about him, starring Mark Wahlberg.