You correctly pointed out two exceptions to US holidays where businesses tend to make their money before or after, but I'm pointing out they're the exception (because of travel) and I see no reason why Voting Day as a holiday would be like Thanksgiving/Christmas i.e. high amounts of travel, most likely it would result in an increase in local commerce and potentially be a way that would hurt the very people it's meant to help.

People travel on Christmas because they have the day off, not the other way around, obviously. None of them are especially large sales days aside a bit from memorial day. It's a really weak assumption being made here. Also, and this may be a shocker, not everyone works a low level job in retail.