Right-—but he is not making it clear that Greeks never “thought” in the terms of “homosexual” or “bisexual”.
How you use words is essential in understanding concepts-—and vocabulary/concept on “homosexuality” was literally changed by a group in the late 1800’s who wanted to change “perceptions” on the widespread activity of pederasty-—because Christianity was so successful in making man/boy sex “evil”. People like John Maynard Keynes/Wittgenstein were not that rare-—nor were they really “shunned” by the elites, although Keynes was having orgies with boys and everyone knew it.
It was only in terms of “erastes-eromenos” which was considered normal for the Greeks and Romans. They never for a minute, thought that marriage/procreation wasn’t essential to the survival of the City-State. The “thought” of homosexual, never existed.
It was actually Kinsey who stated that sex was “fluid” and anything could be made into an “object” of desire—if done at a young enough age and the elimination of Christian morality which he and all Postmoderns reviled because they thought it destroyed “freedom”. Normalization/habituation of sexual practices was a huge determinate in the practice/customs of the people.
John Maynard Keynes invited him to join the Cambridge Apostles, and Wittgenstein left it as soon as he perceived that it was essentially an intellectual sodomite society.
His student and later close colleague, G.E.M. Anscombe, was convinced that Wittgenstein became a strict ascetic and celibate after his military service in the First World War, when he gave away all his money (an incredible fortune, one of the largest in Europe) and rejected "luxuria" in both the sense of lust and luxury.
He was tormented by emotional attachments to certain male friends for most of his life, but as he abstained from sexual contact and self indulgence, I don't think he should be classified with a fertig pederast like Keyes.