I'm not sure how old you are or what level of biology study you've made it to, but hopefully a good education can cure your misconceptions about the way sexuality works.
According to modern science there's a demonstrable variance in sexual activity among humans and other mammals. Supposedly 5-10% of men engage in homo activities and something like 4-7% of the population are pedo. This seal tried to **** a penguin: http://news.bbc.co.uk/2/hi/7379554.stm. This dude tried to **** his patio table http://www.telegraph.co.uk/news/uknews/1583118/American-caught-having-sex-with-picnic-table.html. This dude ****ed a horse: http://www.chron.com/disp/story.mpl/bizarre/6553012.html. It doesn't have to make sense. What's probably "natural" is that absent of a strong moral impediment some guys will try to **** anything and like it. Keep in mind that sexual mores change over time, not sure why that would upset you. Humans originally commonly ****ed their offspring, but incest is now the first of all sexual taboos. Polygamy was once the basis of human civilization but is widely discriminated against today. You're right that binary sexuality or "gay" as a identity is a modern social construct. The Greeks or Romans would have found homosexual "identity" anathema and ridiculous. Sociobiology, which gay activists have latched onto as the scientific justification for being "born gay" didn't even exist until EO Wilson 3 decades ago. Who knows in 50 years the very idea that a dude has to choose between gay and straight sex might seem a ludicrously bigoted idea and "gay" might not exist but even if it's merely a social convention, it's real. You might as well post that you think miscegeny is wrong or you believe in dictatorship as a form of government. It's not a mental illness. They simply worried how gay relationships might degrade unit morale. Consider the case of an NCO doing a solider in his unit up the ass every night. If you were in a position of power and had a romantic relationship with one of your soldiers, could you send him off when you know he could die? Think if you had to choose between your wife or son versus someone else to potentially die, you dont think that would cause moral dilemma? How about the other smucks in your unit depending on your decisions for life and death, if they know you're in a relationship with one or more of the guys in the unit, how's their morale going to be? If you were in a unit where 1/3 of the guys were coupled up are you going to be confident that NONE Of those guys will have biases when lives are on the line? Obviously the solution is that the Army has to come in and to ship someone out. But now the Army is in the business of getting into your business and JAG is out there checking phone records and interrogating people about what they do with whom in the privacy of their own bedrooms. In 1993 the military brass didn't want to be in the business of executing inquisitions among their troops for who is and is not gay, who is ****ing whom in the ass. Which they would have to do since they would have a moral obligation to break up couplings that might degrade discipline and morale when lives are literally on the line. Dont ask dont tell was clearly designed not to discriminate from gay serving in the military but all the negative affects that having open couples serving together could create, else they could have banned gays outright. Two decades ago Clinton would not have pushed through a completely open policy, especially with his precarious position prior to the 94 midterms. Obviously dont ask dont tell will be repealed. It is contrary to our bill of rights. But it's ignorant to say it's all bigotry. A good analogy is how the military tried to shut down wikileaks, although it would violate our principles of free speech and civilian oversight of our military. When someone makes an argument that it might "save lives" or other nonsense it's easy for the weaker-minded among us to throw out rights and go along.
Discussing different pictures used by different groups to make different points is tangential at best. To appease you, I responded as best I could to your non-example about the NRA hypothetically using some picture you've envisioned in your mind that I, or someone else, could hypothetically take offense to. I would have been better able to respond had you provided a specific picture to make your point, but I have a hard time seeing how that would have accomplished anything pertaining to the topic at hand with regard to DADT and the picture used to make the point. Had he used a picture of a field of dead babies with the caption "which one is the gay one," I would consider this wildly inappropriate and equally offensive as well. If you had referenced such a picture rather than linking me to the Iwo Jima Memorial itself, I would have, at a minimum, acknowledged the relevance to the topic at hand and its pertinence to the discussion.
