Atheism is a rational position to me yet every atheist I know is so irrational.
As I see it, personal morals isn't rational. They are based on feelings, what you feel to be right. Feelings are very complicated. Some of it is genetic, some of it's experience, culture/upbringing. It's no wonder that you like Islamic philosophy.
What you like, what you dislike, that's part of who you are. You can't expect other folks to have the same like/desires as you. You have you morals, other folks have theirs. That's fine as long as you don't go expecting to force these personal moral views on each other.
Group morals are a different matter. People on the left or right might have some expectation of your group morals if your part of that group.
Atheism just means you don't believe in a God. That's it. Some groups may see that as immoral but that's their problem. Everything else is pretty much open to your personal feelings. As long as you're not intentionally trying to hurt someone else and not insisting your own personal morals on everyone else, it's all good in my opinion.
If you see transgenderism as wrong for yourself, that's fine. As long as you accept others may see this as ok. Their not hurting you, you're not hurting them. Let them be happy and pursue your own happiness.