I'm not sure how much plainer you need it to be. As that goofy saying goes, "God made Adam & Eve, not Adam & Steve".Matthew 19:4-6, which you cite, does not specifically define marriage as restricted exclusively to the union of one man and one woman.
The bible aside, homosexuality makes no sense whatsoever. It's like having two left hands. But both halves of humanity coming together to make a whole makes perfect sense. It's complete, it's natural, and it works.
HIV isn't a risk for all groups. Uninfected people who are faithful in their lifetime relationships aren't at risk.While I agree with you that each society needs to make its laws based on what its people believe are best and I’m willing to assume, for the sake of discussion, that up to this point our society has been guided primarily by Christian values, I believe your conclusion that as a result we have become the most powerful, prosperous nation on earth to be unwarranted....
Likewise, citing certain infectious diseases, including HIV, to be present-day evidence of homosexuality as an abomination, is equally invalid ... since certain infectious diseases, including HIV, are a risk factor for all people.
AIDS was first identified among MSM. It apparently spread to heterosexuals through bi-sexual relations. Still, even though there are many, many more heterosexuals than homosexuals, MSM account for the majority of HIV infections.
Concerning the US being the most powerful and prosperous nation on earth, it certainly was a result of Christian values, as well as an understanding of who God is. The founders recognized that all men are created equal, and that each one is endowed by their Creator with certain unalienable Rights ... life, liberty and the pursuit of Happiness. That concept set the United States apart from every other nation, and it allowed its citizens to pursue their dreams to the fullest.
If God-haters spent as much time trying to understand God, as they do nit-picking at verses and pointing fingers at the flawed human beings who believe, they might understand the good life that God wants for them, and that living self-controlled, decent lives is the only way to be free. No STDs, no unwed pregnancies, no addictions, stable home lives, hard working & honest.
Jesus said the two greatest commandments are to love God with all our hearts, and to love our neighbors as ourselves. These sum up the law and the prophets.(Simple, but difficult to do.)