Only toddlers
Lets suppose all toddlers in the world are presented the 2 buttons and along with them, so are you. So basically you have no idea how its gonna turn out because its probably just gonna be entirely random. So now, do you vote blue, or red? Voting blue contributes towards saving everybody but carries the huge risk of dying along with probably half the entire toddler population, while voting red contributes towards wiping out probably half the entire toddler population but saves yourself.
The reason why I came up with this variant is because it slighly irks me when people consider toddlers and mentally handicapped people to be eligible voters for this thought experiment because imo in order to take away anything useful from it we must assume that voters understand the situation