I'm going to bet that no one talking about this knows what the apps actually does. Does the app say "Hold this to your forehead for 5 minutes while running to be cured of being gay" ? If so then it could be denied as being a fraud and skip the whole issue.
Along the same line, a vaccination for being gay would be just as bogus, but wouldn't be an argument against vaccines for polio.
I'm going come back on the freedom side. A person can want or not want, whatever they want. Moreover, as a general fear of absolutes, I would be incredibly surprised if everyone who was gay, was so for the same reason. I don't think we know nearly enough about it to make blanket statements.
Apple, of course, is free to do whatever they want with their business, and we are free to buy whatever phone we want, which is why I have a G2.