Why do people still think homosexuality is learned?

I was skimming through The Economist the other day and came across this article about gay individuals in China and the day to day obstacles that they have to go through. The article shared the story of one man who struggled to come out to his parents and instead of being true to himself and being him, he underwent gay conversion therapy to try to fix himself for the sake of his relationship with his mom and dad.

And guess what? As a result, he got anxiety issues, insomnia, weight and hair loss, and minus $1,700 from his savings account. But the thing that he went in to "fix" still remains. He is still a gay individual. So this brings me to my question: if homosexuality is a learned behavior, then why doesn't gay conversion therapy work, like ever?

I mean, if you can learn and unlearn to like something via cognitive conditioning, then why can't gay " behaviors" be unlearned, if indeed it is socially learned? Could it be because the conservative, ignorant people and the fundamental religious nuts are absolutely wrong in saying that people are not born gay, but rather learned it by seeing same-sex couples on TV and/or in public?

I guess so, because, from the following stories about people who underwent and endured the cruel gay conversion therapy, it really seems like gay people are born gay (they are) just like short people are born short and tall people are born tall.