How do you know homosexuals are not patterned by other homosexuals?  
As for "pretending" to know what the intent should be for every sexual act: I am not "pretending"to know anything. I am basing my position on divine law, both natural and revealed. The Church affirms the truth of these two aspects of divine law. And since the Church is "pillar and bulwark of the Truth" (1 Timothy 3:15), what I say is not "pretense" at all, but the truth of the matter. 

Can I assume you are a Christian?