Because I don’t think they are even human if I am not mistaken there’s a sutta where buddha denied that he is human
At one time the Buddha was traveling along the road between Ukkaṭṭhā and Setabya, as was the brahmin Doṇa.
Doṇa saw that the Buddha’s footprints had thousand-spoked wheels, with rims and hubs, complete in every detail. It occurred to him, “It’s incredible, it’s amazing! Surely these couldn’t be the footprints of a human being?”
The Buddha had left the road and sat at the root of a tree cross-legged, with his body straight and his mindfulness established right there.
Then Doṇa, following the Buddha’s footprints, saw him sitting at the tree root—impressive and inspiring, with peaceful faculties and mind, attained to the highest self-control and serenity, like an elephant with tamed, guarded, and controlled faculties. He went up to the Buddha and said to him:
“Sir, might you be a god?”
“I will not be a god, brahmin.”
“Might you be a fairy?”
“I will not be a fairy.”
“Might you be a native spirit?”
“I will not be a native spirit.”
“Might you be a human?”
“I will not be a human.”
“When asked whether you might be a god, fairy, native spirit, or human, you answer that you will not be any of these. What then might you be?”
“Brahmin, if I had not given up defilements I might have become a god … a fairy … a native spirit … or a human. But I have given up those defilements, cut them off at the root, made them like a palm stump, obliterated them so they are unable to arise in the future.
Suppose there was a blue water lily, or a pink or white lotus. Though it sprouted and grew in the water, it would rise up above the water and stand with no water clinging to it. In the same way, though I was born and grew up in the world, I live having mastered the world, and the world does not cling to me.
Remember me, brahmin, as a Buddha.
I could have been reborn as a god,
or as a fairy flying through the sky.
I could have become a native spirit,
or returned as a human.
But the defilements that could bring about these rebirths
I’ve ended, smashed, and gutted.
Like a graceful lotus,
to which water does not cling,
the world doesn’t cling to me,
and so, brahmin, I am a Buddha.”
Note that every buddha is arahant but not every arahant is a buddha so it’s obvious that no arahant is man or woman or transgender no one amongst them is homosexual or heterosexual and not only I don’t think they are human, I don’t think they are even being and I will back up my statement with this sutta
Seated to one side, Venerable Rādha said to the Buddha:
“Sir, they speak of this thing called a ‘sentient being’. How is a sentient being defined?”
“Rādha, when you cling, strongly cling, to desire, greed, relishing, and craving for form, then a being is spoken of. When you cling, strongly cling, to desire, greed, relishing, and craving for feeling … perception … choices … consciousness, then a being is spoken of.
And buddha goes one step further by encouraging people to destroy their body , feeling and other aggregates
Suppose some boys or girls were playing with sandcastles. As long as they’re not rid of greed, desire, fondness, thirst, passion, and craving for those sandcastles, they cherish them, fancy them, treasure them, and treat them as their own. But when they are rid of greed, desire, fondness, thirst, passion, and craving for those sandcastles, they scatter, destroy, and demolish them with their hands and feet, making them unplayable.
In the same way, you should scatter, destroy, and demolish form, making it unplayable. And you should practice for the ending of craving. You should scatter, destroy, and demolish feeling … perception … choices … consciousness, making it unplayable. And you should practice for the ending of craving. For the ending of craving is extinguishment.”