What is the sexual orientation of 'the joker'?
The Joker's sexual orientation is not written into his character.
I think you mistake "sexual orientation" with specific types of orientation. Sexual orientation is a part of every humans make up. A person can not have a sexual orientation. Your sexual orientation is what makes you gay, straight or bisexual. Homosexuality IS illegal in some countries. You can outlaw a behavior but you can't outlaw an urge or feeling.