It's not a fine line to me. If you continue to commit homosexual sex acts you are both gay and condemned. If you don't you are not.
The problem is in someones definition of being gay (homosexual).
To me, having gay sex defines it. So, technically if you are not having gay sex, you aren't gay. So to me a “Gay Christian” is an oxymoron.
As far as “bring a gay to church day” I would say only if you tell them in advance that God thinks that behavior is an abomination. That bringing then to church is an effort to convince them to change their sinning ways. To become a member they would have to publicly renounce homosexuality.
In that case, not many would still want to come to church. I don't believe in “tricking” people into church or “tricking” people into salvation. This is why there are so many hypocrites in church. They were never “real” to begin with.
As you state it, we are in agreement regarding the point of condemnation.
Where we differ, I guess, is that I accept that there are people who find themselves emotionally drawn to others of the same sex, and in that attraction find themselves pulled into your definition of homosexuality.
Is being emotionally attracted to a person of the same sex, in the absence of the act, not homosexuality? From your point of view, it is not, and therefore not a sin.
So we agree in the main. Even in the presence of the attraction, if it is channelled into appropriate expressions, it is not a sin.