If 50% of people choose blue pill, everyone lives, otherwise blue pills die

Yeah I think the results would be different if it were phrased in terms of consequences to the individual:

If you choose red pill, you are guaranteed to live. If you choose blue pill, you will die if less than 50% of people also choose blue pill.

Choosing the red pill isn't selfish, it's logical. There is no good reason for choosing blue. If everyone goes red, everyone's fine. If the rest of the world wants to try to collaborate on blue for some reason good luck to them. Not my problem. It's safer and simpler to go red.

It's not selfish to choose red in this case.

One way has a chance to die. The other way has no chance to die. And the safe choice doesn't force anyone else to suffer the fate you avoided. They can and should choose red too.

No one anywhere should pick blue, not because of "stupid, let someone else take the fall" reasons, but because there is no reason for anyone to take the fall, and the benefit from choosing red does not come at the expense of forcing someone else to choose blue.

Basically the scenario was not as well constructed as the asker probably wished.