Disclaimer: It goes without saying (yet I’ll say it anyway) that these are my personal beliefs here, and I don’t expect others to agree or hold them just because I do.

How would it be ``bad for our country''?

I think that God blesses and punishes countries based on how they follow the moral code that He has outlined. So by publicly promoting something against His precepts, we (the US) are turning away from Him with our actions.

wouldn't they be gay anyway, just repressing?

I think that not all behavior that we are inclined toward is healthy. Case in point: I was very inclined toward sexual activity during my teenage and college years, yet I abstained until I was married. I feel that this was a very healthy denial of my urges and has yielded great benefits. Now granted this is not the same situation because I was denying my impulses for a time where a homosexual would be denying impulses for their entire lives, but the principal of denying what “feels right” is there. I do have struggles with sin that I fight every day that will likely continue until the day I die. God rewards me for my resistance to sin, and is forgiving when I fall. What I must not do is commit blatant sin and expect it to be overlooked or condoned.

And wouldn't it be preferable to avoid making those people's lives miserable? Wouldn't it be better to allow them to be as happy as possible rather than confining them?

Happiness is nice, but it is not the end goal for which humans should aspire, at least in my mind. I’ve seen way too many people pursue happiness and fall deeper and deeper into depression. The happiest people I’ve ever met are those who deny themselves all of their desires and instead pursue the things of God. I know that doesn’t track with your worldview, but it’s been a consistent theme through people I’ve observed and my own experiences.