Correct. At a choice of 'ONLY Red survives' versus 'Everyone survives', we choose the latter. That's all.
Negative. I don't believe anyone is obligated to do anything, certainly not on my behalf.
We have two buttons to choose from. Red gives a highly undersirable result. Blue gives the optimal. So we choose Blue with no thought about others or obligations or begging for help lest the steamroller runs over us, or any of your other crackhead misdirections.
We know the game theory that Blue might be killed by the Red Voters (perfectly accurate), but we don't consider that a serious risk. Most people are not like that, we reason, and will vote Blue. So we vote Blue asking nothing of anyone else, and we win over and over.