You should maybe point her to a few of these forums you speak of
He did stop assuming
His post are open to criticism, suggestions and assumptions. It's what happens when you post in a public forum. Personally I think you posting about animals which is something that you're passionate about(for both the right and wrong reasons) and putting effort into it is great and quite frankly a step up from you posting your newest shit fetish.
My only interest in animals is educational
You told your father in law you thought the cat was sexy and implied wanting to fuck it. You've also admitted to being into beastiality...
I don't think it's just educational interest