Okay, Thork, I'll break your first post down, if that's ok?
There is no s. Straight isn't recognised.
Straight isn't a minority sexual identity. What additional rights would you like for straights? Most, if not all the other letters are fighting for the right to be treated like a cisgendered straight person.
There is also no p. Peadophiles aren't allowed despite being a minority group that is attracted to children.
As others have said, consent.
There is no n. You can't join if you are attracted to dead people albeit that you are also a minority who is discriminated against.
If you're just continuin g to have sex with the corpse of your loved one, would that be necrophilia? You were attracted to the person, not just the fact that they're dead. If you're having sex with dead people who are just dead people, then you answered your question (in a way) later on when you said that the body belongs to you. You're abusing a body which doesn't in any way belong to you and you have no permission to abuse.
There isn't another 'i' for incestuous. You and a relative can be deeply in love, heavily discriminated against and these people don't care.
Are there many people who are
exclusively attracted to their relatives
because they're relatives? If not, then they're not a seperate sexual identity. However, if there are, I imagine that the numbers are so small that they simply haven't applied to join.
There is no additional b. Fancying a sheep is also way out of bounds. Wanting to mutilate your own penis is fine, wanting to play red rocket with the family dog is out.
Consent.
There is also no b for bigamy. You're welcomed if you like both men and women, but not if you like both at the same time.
Bigamy isn't a separate sexual identity. There are plenty of people who are in polyamorous relationships of all kinds. Some are gay, some are straight, some are bi. You fancy each person in that group, not the group
itself.
Who the hell decides what kind of sexual deviance is ok
Society. And the standards have obviously changed. Time was, an interracial relationship was tabboo - or an inter-class relationship.