Coming from someone who works at target, I've never seen a man looking human walk into a female designated restroom. (or vice versa) If their genitals were the opposite I wouldn't even know.
Secondly, you're usually only shopping in target for less than an hour so barely anyone even uses the restrooms.
Thirdly, we DO have unilove bathrooms, it's just not upfront near the doors, as it's usually for handicapped or mothers wanting to change their child's diapers.