The real question is how are people still voting for Yamato?
Actually many people still consider Yamato as the next straw hat, so thinking that she doesn't have a chance is the real copium.
I mean she said that following Oden steps will eventually take her out to the sea, and that's what she's doing now in her cover story.
When Yamato met Luffy the first time, she told him two things:
1- She wants to open Wano's borders (will happen once BB attacks Wano)
2- She wants to join his crew.
thus, it's only natural to vote for Yamato.