You are entitled to your thoughts and opinions just like the OP's T and everyone else, of course. But we are living in a day and age where we actually don't have to rely on what anyone "personally thinks" is the etiology of sexual orientation because we have loads of quality, published, peer-reviewed research about it. None of that data suggest that trauma can "push" someone to experience sexual desire for the same sex.

T's are ethically bound to be up on all that stuff because talking about sexuality is a huge part of what they do--it would be unethical to rely on what they personally thought. You could also reject germ theory and personally think that tuberculosis is caused by CSA and be within your rights to do so; but if you advise your patients of this in your capacity as a physician, you'd be rightly dismissed as a quack and be in contravention of your ethical code and professional obligation.

Out of interest, though, I wonder what it says about your attitudes toward sexual desire for the same sex that you feel that when it is not innate, it is the result of trauma. Could the same be said for sexual desire toward the opposite sex? Generally we think of the fallout from trauma as being pretty negative stuff (eg low self esteem, flashbacks, fearfulness etc.) so when you place sexual desire toward the same sex among those symptoms, well, it doesn't paint a very pretty picture, does it? It suggests that you see it as pathological, no? Well it's not cool for a T to suggest that her client's sexual orientation is pathological. See where I'm going?