Since I have over the course of years of participating in various recovery programs and support groups met many, many people whose sexuality has changed over time of course I do. I have no driving agenda that would require me to assume that people who are trying to change their lives with regard to various compulsions and addictions would lie about a peripheral issue - as you are suggesting. Perhaps you might consider why you champion a version of reality that require you to pretend large groups of people don't exist to maintain the plausibility of your view.
Just because some people have a biological propensity towards same-sex relations doesn’t mean those relations are right or can’t be overcame.
I do believe that a person’s sexual orientation can change with therapy. But I don’t believe a person actually chooses to be homosexual. I think probably they are born that way, but there is also the possibility that it is a result of their upbringing. But I think that is more likely to result in “gay” acting heterosexuals. Although for the record I hate it when people call others “gay” simply because they act a little different than themselves.