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?

What is the Sociology of Sexuality and Gender?

The sociology of gender is the study of gender in society. It examines the effects of socialization and the construction of each.

According to social scientists, sex and gender are two different things. A person's sex defines what they are biologically. Are you a girl or a boy? Male or female? Sex answers these questions. 

Gender, however, is the different social behaviors between males and females and how groups of power have exploited people based on it. I am a man, therefore I will go out and hunt, and protect the family. You are a woman, therefore you will stay back, and gather fruits and take care of the children. Basically, it looks at the different gender roles that society has created.