This is a better argument than the rest, probably the only one worth addressing. You need to understand what nature is. Nature encompasses the entirety of our material world as it pertains to life cycles, water cycles, gravity, right down to physical laws and the theories that explain them.
It's totally misnomic to say "homosexuality isn't part of nature". Nature is what governs homosexuality. And it was never a problem until Jewish value systems came about. Just like serial monogamy was never a problem (it's actually the "natural", majority relationship type. All humans are serial monogomers).
It's also misleading to argue that because something used to be treated medically (by chemical castration, I might add), that it ought still to be "treated" medically. Homosexuality doesn't actually pose a health risk in and of itself, either psychologically or physically.
In fact, it only was ever considered to be harmful to society because of the JudeoChristian values embedded in the social psyche, that deemed it so. Now, those values are becoming more and more a minority opinion on how society should look. That's something Christians have to concede. You live in a uniquely secular constitutional democracy.
This is not a fact. Homosexuality was long condemned by many civilizations. Ancient Rome, many parts of northern Africa and Asia have histories of law and punishment against homosexuality. Islam's history is rich with homosexual condemnation.
As for the natural benefit of homosexuality: it would have heloed naturally limit population expansion. The population expansion problem we have can actually be traced back to Abrahamic religion: giving women no authority over their sex lives. Middle Eastern Islam, many foreign Christian interpretations, and many Jewish traditions, and the Catholic church in many African states and in South America, allow or at the very least promote marital rape, contraception bans, divorce as a man's right only, the sexual and legal authority of man over woman, and the idea that more children is better than less children. This leads to population expansion, and subsequent scarcity of resources and the violence and poverty that inevitably come with it. Secular countries that allow homosexuality, allow females to divorce, allow women to have power over their own sexuality, and promote safe sex, have sustainable populations.
This is theory espoused by LBGT advocates because no one can think of any other attribute for homosexuality. Your argument here is actually a scientific paradox because there is no GENE or any other identifiable difference in either homo or heterosexual tendency. In order for this premise to be true nature would have had to present a distinguishable difference in human species in order to fulfill its purpose of controlling populations. No such difference exists which means that somehow, nature would have to rely on humans committing themselves to homosexuality in order to fulfill nature's goal of reducing populations. And that's just crazy.
Homosexuality specifically, evolved in nature to deal with excessive populations. During any population boom, the percentage of homosexual people seems to increase. It's thought this was to provide extra help with childcare, since humans for many years were raised in communal settings. There are also genetic and neurological tells for homosexuality. It's not simply something that people just "decide" to be. With all the religious damnation and subsequent stigma, the threat of violence or even death in some countries, who would ever decide to be gay if they had a choice?
I will agree that it probably doesn't much FEEL like a choice but will submit and and agree with the post concerning sin addiction.
I should also point out that the founding father's were mostly enlightenment deists, not Christians, and morality is and always has been a phenomenon the specifics of which are relative to the population's majority. The very existence of different moralities between cultures professing the same religion is surely evidence of this.
And the FAR MAJORITY of the U.S. founding fathers were Christian. Sorry. (I'm including 1 of the founders who was Catholic and, thus, also Christian but I'm biased) Here's a rundown.. First Amendment Religion Clauses: Signers of the Declaration of Independence - Christian Background