My evidence that attraction is a choice is as weak as yours is that it isn't. Bisexuals exist. I have heard 1 gay woman, (the president of the local GLYS), in answer to a question, say "I'm gay because I don't do sex with men." Certainly, a man could get her off. Whether she is attracted to the man or not is a choice and that choice is influenced by many factors:
1) Is there such a thing as homosexuality?
2) is homosexuality detrimental to my well-being? (ppl choose to do many other things that Are detrimental)
3) is there opportunity for me to try homosexuality?
4) am i willing to try? weigh the pros and cons
5) Am I truly doing this for me?
6) am i willing to be honest in my attempt despite perceived, possible social consequences? -a key point that may have caused those failed, misguided therapies.
7) after trying it, do i like and can i sustain the results?
-Not a comprehensive list.
A failed attempt by one or 1000 individuals only suggests that all others will also fail.