I thought that I would give my take on why I believe pushing the red button to be the rational answer to the dilemma. In order to do so, I will present a reworded dilemma that operates on the same logic as the button dilemma and explain how the logic behind each dilemma is identical.
My new dilemma
Imagine that there is a vial of the strongest poison known to mankind. Every person on Earth is asked whether or not they wish to drink the poison. Furthermore, they are made aware of the fact that the vial of posion will be split into doses amongst all of the people who also choose to drink the poison. If 50% or more of people choose to drink, no one recieves a large enough dose to kill them. However, if less than 50% of people choose to drink the poison, each of those who choose to drink will receive a letahtl dose and die.
If a person chooses not to drink, they simply do not drink any of the poison.
So, if less than 50% of people choose to drink the poison, the individuals who have chosen to drink the poison will each receive a lethal dose and die.
Why the two dilemmas are logically identical
Committing yourself to drink the poison is logically equivalent to pressing the blue button. In both scenarios, the choice means committing yourself to death unless 50% or more of the population also chooses the same option.
Similarly, choosing not to drink the posion is equivalent to pressing the red button. In each scenario, you choose not to risk your life, even if that mean that those who made the opposite choice (pressing blue/drinking poison) may die if more than 50% of people also press the red button or choose not to drink the poison.
So, the logic of the two scenarios are identical.
Why pressing Red is the rational answer.
Imagine you were asked why you chose to drink the posion in my newly worded dilemma. What would you have to say? That you wanted to save those who had also drank the poison? That you were acting with faith and trusted in others to also drink the poison? But a better question to ask is yourself this: Why would anyone drink the poison at all? Before anyone committed themselves to drink the poison, no one was in any danger whatsoever. The only way in which anyone is in danger is if they choose to drink the poison
Those who choose not to drink have done nothing more than simply refuse to endanger themselves in an obviously irrational and unnecessary endeavor. Those who choose to drink have done nothing but endanger themselves needlessly, as there is no danger whatsoever as long as they choose not to drink the poison.
Similarly, all that the red-pushers have done is choose not to needlessly endanger themselves in an unnecessary endeavor. Any blue-pushers have put themselves in harms way unnecessarily and pointlessly, as no one was in danger before they choose to push blue.
It is as rational to press the red as it is rational as it is to not commit yourself to drinking a potentially deadly poison needlessly.
EDIT* : I should add that no one is aware of any of the choices of other individuals when they make their choice. In either dilemma.