A new question in the 5th installment was exactly that. MetropoliS is going to say as well as display and express its Zero Tolerance, we hope to transcend cultural boundraries, and expose more than say of whats in the Combine. for some that wish this otherwise, alternate scenes have been planned and an alternate version of the film will be supplied.
wait, why bisexual? Edit
as we are aware, the decision to display "middle of the road" was decided as a way to show the zero tolerance and justice of the combine while still staying in relation "straight". we want to "accomplish a field of neutrality" with the audience. we avoided gay/lesbian dislay due to societies current views, and avoiding the film being stereotyped into one of "those" films. though JDSteele is a partial supporter of rights. we wanted to "move out of the comfort zone of the audience, and yet not travel too far from home for them" we understand these scenes are only 2-5% of the film, but we wish to put this disclaimer here to explain and remember, if you wish to recieve non-issue copy, we will be happy to give it to you when the movie is completed.
Wait a minute, why not just females? Edit
the reason behind this answer to to clerify this movie isn't a porno, it is not something you will get off to. as when we show both sides of the bisexual for both sexes we are trying to show black and white as the Combine are, showing both sides to illustrate the fairness, on that matter, that the Combine have on the situation. Further more, Marie Antionette being a "straight" figurehead opens the male end of the discussion as she would never find interest in the females side, though true to story she is a bit of a sexist, but nothing more.