Well, the people who don’t share my idea about what makes the world better are just making it worse. Obviously. 
… seems like an awful big task… no, I don’t think we can each and only stand the weight of the world.
This quote, from Norman McLean’s A River Runs Through It, comes to mind:
“So it is that we can seldom help anybody. Either we don’t know what part to give or maybe we don’t like to give any part of ourselves. Then, more often than not, the part that is needed is not wanted. And even more often, we do not have the part that is needed. It is like the auto-supply shop over town where they always say, ‘Sorry, we are just out of that part.’”
I’m not really sure I trust someone else’s idea of “better.”
But we certainly should at least leave things as we found them, not worse.
My parents taught me to always leave it a little better then you found it. For me this applies to everything, not just the world.
Explain why this makes less sense than anyone else being murdered.
I understand why it makes less sense for someone who believes in the sanctity of life to commit a murder, but to be murdered??
I voted no. I have a desire but not an obligation.
I’m only +1 this because the OP asked for it. I can say it longer, but not better.
I don’t think the world is in great shape at the moment, so I think we should try to improve it.
For those who say it’s their duty to not make it worse, but not their duty to make it better - do you feel the world is in good shape at the moment?