Correct, he is not. He is, however, saying that the Catholic Church has no position on the origins of homosexuality, countering your claim that the origins of homosexuality are known from the Catechism and Scripture. It also counters your claim that a Catholic must believe that homosexuality is not biological. This is a topic we are free to differ on.
His study reeks of bias because he is presenting what is effectively an opinion piece as a scientific analysis. As a scientific analysis, it is intensely biased to the point of being unreliable. But he also makes false conclusions and overly broad conclusions in error as well. I am not providing you a scientific analysis, but I am giving you a theological analysis consistent with doctrine that I recognize could be fallible. I could possibly be wrong in the future, but contrary to your claims, we do not have enough scientific evidence to know one way or the other whether homosexuality is biologically innate or not.
The problem with this debate, however, is you do not recognize that your opinion may, in fact, be fallible and are attempting to force everyone else to believe what you believe on an issue that we are under no obedience to believe in any manner on.