Is there a reason why rape isn't explicitly prohibited itself? That it isn't considered a commandment "Thou shalt not rape" (for instance) in any of the major religions? Not just the Abrahamic religions, but in Hinduism or Buddhism?
If we as humans are well aware of the violence of rape, why is this act largely ignored in favor of stressing the sins/crimes of lying, stealing, coveting, or becoming an apostate?
Well, I can't speak for Buddhism, but in Hinduism, you're sort of free to make up your own mind about........well everything really. You're not bound to any one scripture. You're not even bound to any one book or central figure like the Abraham religions.
Because of this, you will find pretty much every single belief under the sun in the Hindu community. And not just about God/s, but about literally everything.
Usually, if any scripture of any "Holy Book" does seem abhorrent according to modern understanding, then Hindus just ignore it as something without merit, reflective of a more "unenlightened" time and then focus on other scriptures.
Sexual assault and rape could very easily be construed in Hinduism as against both Dhama (roughly meaning duty) and as bad Karma. Against Dharma because, well. Sometimes you will find that sexual satisfaction is considered a large part of successful married life, both physically and spiritually. If a man does not satisfy his wife or vice versa sexually, then that is usually considered a "sin" as it is part of his/her Dharma to satisfy the partner. If he or she forces sexual gratification from their partner, then you can argue they are again commiting a sin. Because it is not only giving into a selfish and flesh based vice, it is ultimately damaging the spiritual connection to sexuality of said assaulted/raped partner.
Bad Karma because obviously sexual assault and rape causes demonstrable harm against a person, therefore a "sin" regardless of circumstance.
So, not explicitly prohibited as far as I know, but you could certainly build a strong argument that according to the philosophy of Hinduism rape and sexual assault should never ever be tolerated, regardless.
As it stands, I haven't really heard the word "sin" at all during my upbringing as a Hindu. Possibly due to translation issues on my mother's part (she speaks "Fiji Hindi" which is less influenced by Sanskrit than "India Hindi") and what is labelled a "sin" is usually just bad Karma, against Dharma or just being a dick. Partly because, well, Hinduism is more based around philosophy than Dogma. Generally speaking of course.
As to why people largely ignore it. Perhaps that's more to do with the fear people have. Rape and sexual assault is not only physically traumatizing like theft or murder, but it's like an ultimate violation of a person. Sexually, physically, mentally and a violation of one's personal anatomy. Therefore slightly more unfathomable to people who have not experienced it first hand. Death is something we can easily sympathize/empathize with, because of the culture we have about honoring the dead and most people have or know intimately someone who have lost a loved one (even if it is a pet.) So much more easily fathomable (at least mentally) than something like rape.
If someone is sexually assaulted/raped in a society, the common reaction is to reassure oneself that something like that couldn't possibly happen to you. People start to panic at the "unsafeness" of society and then start to make excuses as to why it happened to the person and therefore excuse themselves (at least mentally) from such a scenario occurring to them. "Oh they dressed like that, oh they were out late all alone, oh they were flirting, oh they were blah blah blah." (You can even find such reactions for victims of murder or theft.)
It's a basic psychological reaction, right? Then because religion is often a large part of one's life, you will find people of varying faiths bring up scripture/texts/books/examples to justify and then brush the "unseemliness" of it all under the rug, as it were. Or one could argue that people came up with justifications by imbuing it into a religious text to begin with.
