To begin with, it's not strictly true that "homosexuality" was alright in early societies, because "homosexuality" wasn't a thing a lot of early societies had a concept of. Much like "human rights" or "race," "homosexuality" had to be invented! Ancient Spartans didn't consider themselves homosexual when they had sex with men. Rather, the important distinction was between the "active" and "passive" role, with the active role being the masculine superior and the passive role being the feminine inferior. Romance between men was not considered homosexual and a man may have many lovers of either gender. Female homosexuality varied widely even within cultures, as the importance assigned to females increased or decreased. A good example is, again, the treatment of female homosexuality in ancient Greece, the most famous example being the poet Sappho from the isle of Lesbos.

You can see this divide strongly, again, in Viking-age Scandinavian societies. Odin was famously accused of practicing "seiðr ," which is a sort of Scandinavian shamanism. It is taboo for men to practice, as its central aspects of manipulation and discretion ran counter to the straight-forward and direct masculine ideal at the time. Historians think an artificial phallus was involved in some way in its practice, but I don't have any sources at hand to provide more detail.

Another good example are the Zoroastrian Sassanid Persians, who believed that love between men was unseemly. Ancient commentary suggests that men who had intercourse with other men were consorts of demons, or were themselves demons!

I am really more of an ancient and middle ages history buff, so I can't say why the idea of strict sexual roles became such a monolithic thing and why it became taboo. Hopefully somebody with a more thorough understanding of modern sexual politics can come in and fill in.