Not for ALL homosexuals, but for some who seem to decide later in life, it can explain what happens. Others have been abused, or simply introduced to homosexual acts at a very vulnerable age, when their curiosity is peeked. Women (A lot of them!) are lesbians because they can seek pleasure without what they deem danger, of pregnancy. Some are what is called 4 year lesbians, through college.
Bottom line, there are many reasons they choose the lifestyle, it isn't as simply as why, but it is a behavior and a choice.
But they are NOT born that way.
Are you sure? You've certainly got an opinion on the matter, but if you ask a homosexual, he'll very likely tell you that he's always been that way, and at least some of those guys will be telling you the truth.
The question of "why" is probably far more complicated than you want it to be.
Most of what you said makes sense. But, why do you insist that they aren’t born this way? Please use logic and thought rather than a recitation of your religous books.