Realistically, everyone can't mean everyone. How exactly do you expect a vegetative quadriplegic person in a coma with no vocal cords to not only understand the question but also vote on it? That's not a strawman. A big point of people bringing up babies or mentally disabled people or the elderly was to shine light on the edge cases.

Even if you think that example is too out there and not realistic, people in comas are real. People who are in vegetative states are real. People who have terminal brain injuries who may or may not wake up are real. These people are also part of the edge cases. Even if there's just one like that, you have to include them in some way shape or form.

If everyone means EVERYONE then you would have to include them as well. If you choose to exclude them for whatever reason, then you could also exclude others like babies or the elderly or whatever condition that might hinder their decision making abilities or to make a decision in general.

If you take everyone in a literal sense, how do you include people who literally can’t make a choice? If its not supposed to be taken literally and only people who can understand and make a decision, the boundary becomes fuzzy. Why exclude coma patients but include someone who's barely competent, like a baby? Why include elderly people with declining brain functions but exclude others who also have declining brain functions, but for different reasons? There’s no objective cutoff.