Okay, let's go further down the rabbit hole...
How would we define being "gay"? Is it merely same sex attraction?
Consider this: a decade or more ago, there was a Super Bowl commercial that showed various provocative shots such as a leg with pantyhose being pulled up, long, healthy hair, a close up of eyes getting makeup put on, etc. In the end, it was shown to be a bunch of dudes getting made up to go watch football or something like that. Before that, however, some of the guys I was watching the game with were vocally admiring the attractive "ladies". Now, as far as I know, all of them are heterosexual in tendency as well as action, but for a moment they were attracted to members of the same sex. Granted, they were attracted to the feminine qualities of what they saw, but I think it shows the confusion that can express itself in regards to media.
Let's look at another issue: I know of at least one fellow who is quite attracted to female body-builders. How do you define someone who is attracted to a member of the opposite sex that has more same-sex qualities than opposite sex qualities?
Lastly, I was in a Bible study with a guy who used to be a practicing homosexual, but through Christianity turned his life around and is now married with children and so on. (his words, not mine) Let's say, for sake of argument because this is something he didn't share one way or the other, that he is still attracted to men, but through an act of will, only practices sex with his wife. Is he gay, or is he straight?
There is a bit of mystery around sexual attraction, of that I think we can be sure, but it gets much less murky when we go into sexual activity.
As to a genetic component... perhaps a proclivity is possible, but as you have cases where identical twins can have differing sexualities, I would have to highly doubt that anyone is "born gay". Although, there might be un- or sub-conscious pressures that take "being gay" out of a straight-forward decision, I do think this is much more of a "nurture" than "nature" issue. ...but our "nature" is now fallen, so I could very well be wrong.
Why do we care? I revile, I am impure, I have stolen, and coveted and any number of other sins. However, I don't try to make people think those are good or noble actions. I turn away from them, and repent of them, I disgust myself when I find them in me. What sins are we being asked to admire and applaud, support and uplift? Even if we were to consider abortion an act of murder, we have no where near the popular call to uniformity from those who support it, than we get from those who support LGBTQ issues.
But, and I think this really will be lastly, we should never forget that we are flawed individuals with no self-merit of our own. When we speak against homosexuality, we would do well to do so in humility, being sinners saved by Grace, ourselves. I know that I struggle with pride a lot, and if I had to make the call, I'd say that is a worse sin than sexual immorality. Call on your brothers and sisters to repent, but don't do it from a high horse.