Christian missionaries often are sent on paths that incur diseases. That alone does not define sin.
You're missing the point. Disease is not the focus of the argument. The "equality" movement labels Christians as bigots who hate. Christ followers hate all LGBT - that is their message. Every day is OPPOSITE DAY with liberals. They always accuse the messenger of what they are guilty of. Sodomy produces disease - 100% accurate. The equality movement always gets to change the argument. The Christ message is life. The equality movement cloaks their message in "love" and peace when in fact they are promoting a culture of death and disease. Get them to defend that they are promoting a deathstyle not a lifestyle. When they change the subject get them back on point. They cannot defend male on male sex. They lose every time.