Paul heard a Judaizer say "Cretans are always Liars." The source is a Cretan philosopher named Epimenides. Showing the distinction of contradiction... I think Paul was a learned enough man to expose the false prophets, for making a show of knowledge that the statement is paradoxical... for the Judaizer told the truth, but in that truth were indeed a veiled lie. Showing "Cretans are always liars" is itself a lie, as that syntactic idea exposes the unbeliever and the Judaizer, that even when telling the truth, they still lie.

The first and most blatant reason,
Is that it is dirty. Butts and mouths are not
Orifices  for sex organs.
And all the other ways
Seem to be artificial
Or not so satisfying.

It is also a non reciprocal way
Of having sex. There is always
One receiving pleasure
And another not.
Meaning it can never be equally satisfying.

It is self centered.
Homoeroticism is a sign of narcissism.
It develops in the minds of those
Who are selfish. To desire one's
Homogenous sex, means one
Has a desire for their own form
And not the opposite form.
Meaning, their libido is turned inward
And when this happens it is classic narcissism.
You can tell by the voice acting men use
That they are being narcissistic;
And the women make themselves look like men.

It skews the Logos.
People who are homosexual
Cannot---I've never met one---
Know right from wrong on any
Basic level. Therefore, it creates 
A slippery slope where it slides
Into worse and worse behaviors.
Such as right now, with Pedophilia
Being attempted to be normalized
And men competing in women's sports.
People who are homosexual
And those who accept them
Cannot know what is good or right
In order to distinguish it from evil.

It also creates a strain on the supply
Of healthy sexual partners.
Those who are homosexual eat up
The surplus of mates, and therefore
Create scarcity for spouses within the culture.
This, in turn, spreads frustration
And increases the occurrence of Involuntary Celibacy.
Because spouses are harder to come by
When three out of every fifty people
Are cut from the gene pool.

And finally, it does not create life.
It, being purely hedonistic,
Encourages others to view sex
As a toy, and not a serious bodily function
Which can create a human life.
Thereby, Homosexuality leads
To an attitude about sex that it can be
Merely about pleasure.
And thereby, it causes those
Within the culture to view sex
Hedonistically. And thereby
It leads to unwanted babies,
And therefore abortions,
And therefore unloved children,
And therefore it destroys
The culture's fidelity.
As, when a culture's view on sex
Is skewed, it cannot be happy.