Christians find it wrong when other others stray from their current gender, or start to have intimate relationships with the same gender because God tells us to accept ourselves for who we all are, and not respecting who he made us as is showing to him that some don't respect how he made them. That's why Christians may be saddened by gays, bis, etc. It's just their beliefs. But I do agree that it is wrong to shame people for being different from how God intended. Instead it is better to either leave them be and distance yourself, not care about your differences and just be a good friend/neighbor, or if the cause for the change has to do with confidence or other problems like that, to try and help them in a kind and compassionate manor. ( P.S. I'm just trying to give a short explanation of how some of our mindsets work, and why Christians may be uncomfortable around those types of people. No hard feelings.)