This is my first comment on Wikipedia, and I have not yet edited an article.
I began reading Science Fiction back in the 1960s around age 8 or 9.
In 1995, I became a fan of "Alternative History", when I discovered Newt Gingrich's novel, "1945". I have also read The "What If?" series, "In The Presence of Mine Enemies", "West Of Eden Series" and "Hitler Victorious". I am curious as to why "Alternative Historical" Novels are classified as "Science Fiction", the way that "Star Trek" and isaac Asimov's books are Science Fiction? "Alternative History", in my mind at least should be a Genre all its own, IMHO.
Of course, "West of Eden" (and "Return to Eden" and "Winter in Eden") is classified as Science Fiction, but it represents what might have happened if that Big Rock had not wiped out the Dinosaurs 65 million years ago, so I suppose it could be in either Category, but other "Alternative History" should not.
I realize that many Alternative Historical works contain many new inventions, but that alone, does not make something "Science Fiction". When a novel, TV show, or in the case of "The Man in the High Castle", Web Show, has, as its main thrust, to show us what "might" have happened in History, then it should be classified as "Alternative History" and not as Sci Fi.