Looking into this question I wonder about several things. I respect the merit of the question but also see the discrepancy in the importance. I think that posing this question through the context of the military cuts the question short in my eyes. Living in a country where military service is optional and considered a career I can't see them guaranteeing any rights to soldiers. I don't understand why anyone would join the service, and if they did why they would expect any rights or guarantees of equality is even more perplexing. Your sexual orientation also seems irrelevant in context of the army.
You don't mix your personal life and your career in any other field why make it clear in that one. Of course I see the implications of having to live with other soldiers and the resentment that may occur between soldiers who are openly gay or lesbian. Being heterosexual you may feel uncomfortable with another person looking at you change when knowing they could be attracted to you. But you have the same protections of sexual harassment as anyone else.
So now that I have made my point of view a little clearer here is the answer to the actual question. The book is asking if being open about your sexuality is important for ensuring self-respect and a sense of dignity. Through the eyes of Ruse it is. He constantly states that "naturalness ought to be defined in terms of culture and not simple biology." What Ruse is saying is that when people state that homosexuality is unnatural they are actually confused on the definition of natural, that they are creating their belief of what is natural based on culture not biology because "species after species, right through the animal kingdom, students of animal behavior report unambiguous evidence of homosexual attachments and behavior." That the biology of animals, which we are state no definite lines of what is ok and isn't sexually. I don't know if I would go so far as saying that Ruse believes you have to state your sexuality openly, or that if it benefits you to do so.
But I do know that he would disagree with the current actions of the military on dealing with homosexuals. Because those actions are considered perverted by the military and Ruse states this about perversion, "a perversion involves a breaking not of a moral rule, but more of an aesthetic rule." So in fact he would say that the military has the wrong views on the subject and that the acts are not perverted but aesthetically unpleasing to some. It is much simpler to answer these same questions through the eyes of John Finn is. He clearly believes that homosexuality is immoral.
He writes this on the subject, "it is destructive to the common good. Because a stable family life is of fundamental importance to the community, the state has a compelling interest in denying that homosexual conduct is a valid and humane lifestyle." Since the military could be considered an extension of the state, he would not believe that any military officers would have the right to practice homosexuality. Whether they state it or not it is clearly against his belief.