Admiral Adama said:
I'm fairly certain you can't definitively say that homosexuality is out of bounds in the natural law definition. Homosexuality is observable in nature, both in animals and humans, throughout recorded history. It might not be common, but it is not unnatural.
I also think, explaining, and rationalizing away homosexuality as exclusively a pursuit of pleasure cheapens the actual reasons that people partner and share lives together.
It's not a question about whether or not something exists. Vice and evil exists in the world. It's violative of natural law. Murder is a really observable thing in nature. Although it's probably defensible in your mind as long as the murderer found it pleasurable.
I think lots of people pursue relationships to serve their own interests. That's not unique to homosexuals. It's just that their relationships are inherently immoral.