the qlikview colours green white and grey fit with the basic aql design. All your males are white because they can logically be selected without moving away from your selection of gender='male'. they are not green because their names have not been selected.
If you want them to be selected you would have to write a macro which woud chnage the status of the User field to "selected" for all those that are "possible". This would mimic the "select possible" action you get with the right button click on a selection box.
The macro would be fired each time you change the field gender (male/female). You woud have to be careful about any other selections which could be or have been made in your document.
The macro would include the line