Do we need God to tell us what is right or wrong?
Right or wrong about something is relative,
determined by men for their own interest,
homosexuality, is it right or wrong?
It is subjective, not absolute.
Right and wrong was symbolically the tree of knowledge of good and evil. The problem with law, which separates into right and wrong is it is not always easy to differentiate subjective from objective laws. Objective has a logic to it, while subjective is more about emotional appeal and is not objective since it may not apply to all but will be force upon like it is objective.
For example, stealing is objectively wrong because it creates costs/defensiveness within in all cultures at any time in history. The height of a women's skirt would be subjective knowledge/law of right or wrong, since it changes with time and/or culture. The subjective aspect of knowledge of good and evil is relative, but the objective standard is not.
If I throw a rock and hit your head this is wrong because the cause and effect of physics will result in injury. This will be consistent with all humans, in any culture, at any time in history. This would be law of God. If say a particular word, and it bothers you, this sound/reaction may not apply to all humans, in all cultures at any time in history (gosh darn it). This subjective law of good and evil and is relative. The first is law of god and the second is law of man and can lead to problems not solutions.
As afar as sexuality laws, the primary purpose of sex is procreation at the level of the DNA. Because this prime directive is so important to survival, nature evolved carrots on the string make sure the prime directive is satisfied. The compulsion and pleasure of sex is the lure or a means to an ends and is not the ends by itself. The carrot on the string is subjective. Homosexuality, cannot by definition. lead to procreation. It is stuck at the carrot on string, horse running in circles for the carrot; firmware glitch.
An analogy is eating, which is needed for the fuel and nutrient requirements of the body. Since this is also a prime directive connected to survival and health, there is also a carrot on the string which is the pleasure of eating. This pleasure is designed to assure we eat enough to satisfy the base requirements of the prime directive. If food had no taste or pleasure people would not eat enough. A dog will eat road kill that has been sitting because their carrot is strong assuring their survival.
Relative to eating, some people get stuck at the carrot on the string and eat only for pleasure even beyond the needs of the body. The horse is busy chasing the carrot and is not moving forward to goal; water, in an objective way. The natural firmware; driver, has lost control of the horse due to a firmware glitch. This type of behavior does not follow natural law, but is based on subjective law at the level of the carrot.
Laws that address the carrots on the string, like some foods are clean and other foods are dirty (good and evil foods) are subjective laws of man which change from culture to culture and time to time. The prime directive is objective and will result in predictable cause and effect based on bio-chemistry; obesity/sickness or health.
Laws against gluttony would address the objectivity of the prime directive. To remove subjective law, there would be no food choice laws, other than moderation. Science would agree, if the goal is health.
I remember thinking about ancients laws against eating shell fish. But if you think about it, shell fish in a hot climate without refrigeration can spoil quickly. This carrot would be restricted not due to law of man but objective laws that science could support based on those primitive conditions. This objective law does not apply today if precautions are used. It has become more of a subjective law for today; only used by certain cultures.
In modern times, science and medicine are used to mop up after people. I could eat bad fish and then go to the emergency room to get my stomached pumped without any net impact on health. I can eat to I become 500 pounds and then check into a medical facility for a restricted diet to cheat nature. These modern mops can confuse things. It is not natural to eat rocks but if I have a medical staff on call I can create the illusion this is arbitrary and subjective and not based on objective standards. I go back to natural and mop free and then do the logic analysis to make sure objectivity is not being made into subjective because of prosthesis. God's law is based on no mops.