i can't speak for the quran as i've never read it, but the content of the old testament isn't meant to be taken literally. most of it is essentially a collection of stories that were originally passed on through word of mouth and written down by various authors (if you read genesis, for instance, you'll notice that there are two versions of the story of earth's creation and noah's ark that completely contradict each other: this indicates the story has been related by two different authors). while there's no way of finding out what their original intent was, it's quite likely that many of these stories were intended as allegory and not to be taken at face value.
as such, there are tons of rules in the bible that have been swept under the rug, while the christian community instead opts to place emphasis on a select few. for instance, leviticus states that one should never mix wool and linen garments. this was possibly due to pagans wearing clothing made of these materials at the time. a rule like this would not be relevant in our current culture. while the main ideas behind a religion, such as the figure being worshiped and how worship is performed, will remain the same, many aspects of the religion will adjust over time to suit the current culture.
I see your point. Qur'an is a lot different than Bible, however. Qur'an doesn't have any other versions or an old testament, and it's not made by stories. It's written by Mohammad and his other "prophet" friends. He wrote down the verses and such (apparently Allah spoke to Mohammad and told him what to write down).
But still, there is a lot of discriminative and violent verses in Qur'an. It's also the same in our daily life Qur'an, the same rules remain. They're enough for anyone to consider Islam to be a violent and discriminative religion.