It seems like you’re saying the lack of anonymity will inflate support for a union. I.e. organizers will be able to pressure people who would otherwise vote no on a union. Frankly, I’d be worried about the opposite. Knowing how aggressively amazon is fighting unions, if I worked there i’d hesitate to put my name down on paper - when I wouldn’t hesitate to vote in a secret ballot. If that’s the case, 50% support implies a stronger majority.

Maybe that’s not always the case, but that’s what I’d guess is happening in this case.