Homosexuality has been a conundrum to evolutionary biologists who viewed behaviors from the peephole perspective of reproductive efficacy.
It is silly to think that the purpose of life is reproduction. A sense of meaning in life derives from its enjoyment. Many behaviors are aesthetically decided, from choices about what to eat to preferences for certain friends and mates. Hence the broad meaning of the term “taste.”
The biological urge for intimacy propels sociality in many ways. Sexuality is an integral facet of social psychology, extending beyond acting as a driver for propagating the next generation.
The want for satisfying connection with conspecifics motivates all productive social interactions. Behaviors are by definition physically expressed.
From this perspective, the commonality of homosexuality is unsurprising. Homosexual behaviors have been observed in over 1,500 animal species.
Ishi Nobu, The Web of Life, BookBaby (2019).
Julia D. Monk, “An alternative hypothesis for the evolution of same-sex sexual behaviour in animals,” Nature Ecology & Evolution (18 November 2019).
“A new theory argues same-sex sexual behaviour is an evolutionary norm,” The Economist (28 November 2019).