To be honest I'm not really sure its as simple as merely "being gay" that's the problem when it comes to church congregations. A homosexual orientation is simply a condition that exposes one to homosexual impulse and desire. It does not, and cannot, make people engage in homosexual behavior.
I don't think that gays "choose" to be gay. I don't think its possible to "choose" who you find attractive. Some gays claim their condition is genetic. There's no proof of that, and even if it were so, it wouldn't nessecarily mean its natural. Autism is genetic, but its not natural. Its a genetic defect. The homosexual condition may be the same way, especially considering the natural state of the human body does not have "parts" that are designed to accommodate homosexual activity. So a genetic defect sounds more plausible than the claim that homosexuality is natural to the human condition. Myself I think the homosexual condition may be developemental. At any rate, I don't think gays choose to be gay. Yet living out a homosexual lifestyle is entirely a choice.
There are a few places in the Bible that explicitly condemn things of a homosexual nature and, as far as I can tell, they all focus on homosexual behavior, not on the state of experiencing an impulse (temptation) to sin. So in the grand scheme of things I don't think it matters what a person's orientation is, or how they got it, but rather what they do with it. Simply experiencing an unwelcome impulse or temptation to sin is not itself a sin. The Bible says that Christ experienced the temptation to sin in Hebrews 4:15 , yet it said that He never sinned. Now, endulging in the tempting thoughts and wilfully engaging in fantasy about committing a sin is the same as committing the sin itself ( Matthew 5:28 ). But if a person truly loves Christ and has a condition, be it a genetic defect, or a developmental issue, and he or she struggles with the temptations that his/her condition brings, and they choose to fight the urge and live a chaste life for Christ, then that's a truly amazing committment to Christ.
So I don't think that anyone ought to be put out of his/her congregation simply for experiencing the urge to sin. If that were the case we all ought to be kicked out, since we all feel the urge to commit many sins on a daily basis. However, if the person has chosen to live out a sinful lifestyle and ignore God's commandments and submits to the urge to sin instead of to God's authority, then I can understand the congregation putting them out for the sake of the body of Christ.