Wait....the old shit in the Koran bothers you but the old stuff in the Bible does not? There are some pretty fucked up things in the Bible. Why is one old religion bat shit crazy and the others are so pristine?
Whataboutism.
I know plenty of Muslims and none of them believe in that old shit in the Koran.
Anecdotal evidence, but trust me...they do believe in that "old shit" in the koran. Here's a video of a bunch of "normal" muslims that don't believe they are extremists, until the imam starts asking them basic questions and turns out they're all batshit crazy like the woman in that video.