Threads like this should be treated with delicacy so I agree on some part that they it shouldn't be located on a forum such as this but I see that you needed and outlet for information because you don't understand, which I get.
I am actually transgender myself (Female to Male) which im very open about because its extremely accepted in my general area so not to be stereotypical but I'm assuming that you're somewhere from the south or in the North Carolina region?
Being transgender is not a mental disorder what so ever, there is a mental disorder that is correlated to transgenderism which is Gender Dysphoria "the condition of feeling one's emotional and psychological identity as male or female to be opposite to one's biological sex." and its closely linked to other things such as depression. Which is why you need to understand that calling it a mental disorder when its not is not only extremely disrespectful to people that are transgender but also to people who have real serious disorders. Also it can be extremely affecting to people that are transgendered and currently suffering from depression, you have no idea how harmful words can affect someone's entire life.
Gender Dysphoria is treated the correct way; the person would go to a gender therapist which after talking to for a while would help them work through and understand their gender identity, if needed one would get suggested to an Endocrinologist a doctor who would help them get the hormones of their preferred gender. NOTE: NOT ALL TRANSGENDERED PEOPLE DECIDED TO DO HORMONAL TREATMENT, IT IS A PERSONAL PREFERENCE ONLY SUCH AS SURGERY. (this is also all from my own personal experience)
As for the Bathroom Bill (I think its actually called the House Bill 2?) like Giggums said, doesn't even have to do with Transgendered as a whole its just used to target the group. I'm sure you can at least understand that Gender and Sexual orientation are two different things, who you like is not affected by your own body. So the idea of harassment doesn't even have to do with one's gender, any one can harass any one, but its just used to demonize transgender as a group because people still don't believe its an 'okay' thing.
However the main parts are; Transgenderism is NOT a mental disorder, they DO need more protective laws because in the eyes of the law they are seen as 'non-people' which is NOT okay it doesn't matter who you are you should still have basic rights, and the bathroom bill should not be targeted at transgenders since it has nothing to do with the group as an actual whole.
Shocker alert; Transgendered people go to the bathroom. Its surprising, I know.