Yes, I would try to stop a child from running into the street. Yes, I would warn somebody if their actions are causing them harm. In the first instance, a child who runs into the street and narrowly escapes death will probably learn from his or her mistake. However - in the second scenario, it is perhaps likely that what we perceive as harmful, in fact is a source of pleasure for that person. Since he or she does not see the harm in it, he or she is not going to listen. My responsibility is to always be of help, never to harm.
What is the difference between a spiritual disease and a physiological one? Say your best friend has schizophrenia, a diagnosis made after you have known him for years. Suddenly, he is not the same person you knew for so long. I am willing to bet that, Christian as you are, you will remain his friend, no matter what. If his condition deteriorates to the point of institutionalization (sp?), chances are you will visit him and let him know you are still there for him.
Now, replace the schiz with homosexality. And the institution with a relationship with another man. Would you still do the same?
I have had friends and co-workers over the years who were homosexual. I currently have a boss who is. As individuals, I treat them no differently than anyone else, but I don't attend their parties or partake in socializing with their "inner circle", nor do I believe it would be appropriate for me to do so. Would I be bothered if they contracted AIDS? Yes. Would I visit them in the hospital? Maybe. Would I be there if they needed me? Sure. Would I tell them that I thought what they were doing was acceptable? Absolutely not.