Irony comes in because (obligate homosexual men, who what most are concerned with) were not "born that way" at all, since male homosexuality almost certainly is the result of a childhood infection.
Worse still, homophobia (or homoaversion, as it should properly called, according to Greg Cochran) is itself heritable, at least 54% so. Yes, homophobes were much more "born that way" than homosexuals themselves!
It doesn't get much more ironic than that.
But the "born that way" meme does speak towards the prevailing attitude towards genetics. Nothing undesirable can be much heritable, for if it is so, it is seen as (not exactly accurately) being immutable. Hence, this is why sexual orientation can be inborn, but IQ, sex, or racial differences cannot.---
Intellectual consistency isn't exactly one of the first phrases that comes to mind when characterizing the contemporary progressive left, but isn't there just a little bit of uncomfortable cognitive dissonance felt among votaries of the Cathedral that the born-this-way message (with regards to homosexuality) is the biggest story coming out of three hours of pop culture autofellatio that is the Grammy's? So many other characteristics that have similarly innate and unchangeable (or at least inelastic) biological roots--like IQ, athletic ability, physical attractiveness, personality traits--are treated as though they are amenable to change through education and intervention.
Mock the "right wing conservatives" who think homosexuality is a personal decision, but Teach for America to make low IQ kids from the urban core into college material and undergo 10,000 hours of practice to become the next Tiger Woods and change cultural constructions of what constitutes beauty to make sows like the woman who sang with Macklemore start being perceived by red-blooded men as being as attractive as the cheerleader next door and foster an ownership society by giving free houses to people with poor credit to make them more conscientious!
To make the inane spectacle richer still, the thing being celebrated by those who superciliously parade their belief in evolution as evidence of their scientific credentials is a Darwinian death sentence. What's worse than syphilis, anemia, obesity, dementia, or any of so many countless other diseases, maladies, and conditions when it comes to evolutionary fitness? Homosexuality, of course.