All - or nearly all - of us face some sexual temptation. Some of us straight temptation and some of us gay temptation. The issue is not in being tempted, but in what we choose to do.
I reiterate: being gay, that is, finding oneself primarily attracted to members of the same sex, is not a behaviour. It's behaviours that are condemned, not the manner in which one might be tempted. The Scriptures say even Christ was tempted in every way as we are! (Note, for those playing along, there's a reference to Scripture).
And this comes back to the point I made earlier; if we don't share the same basic understanding of the world and how it works, it's pretty difficult for Christians to have meaningful discussion about how we should live in light of that understanding.
That in a secular, pluralist society, Christians can't expect to control how everyone else behaves? Yes, I would think so.
I'm not sure precisely what you've experienced on that count.
The comment I made, the day it was announced that same-sex marriage would become legal in Australia, was that through the debate, the message many gay people (and those around them) had heard from Christians was that God didn't love them and the church didn't want them. And that our job now was to get a different message out there. I still think that's true.
I think there are different issues in play for businesses. And some Christians might need to modify their range of goods or services, so as to be able to treat every customer equally. (Eg: if you don't want to supply product A for a gay wedding, don't supply product A at all, kind of thing).