Why are there so many cruel old testament laws that even promote murder (especially against women)?

When you read the context of the society in which it was written, you actually see that the provisions and laws were quite "progressive" for women. It actually gave women rights and ways to defend themselves and prove themselves innocent from wrongful claims. There is a book about Jewish jurisprudence which goes into detail about how hard it actually was to kill people back then. It was a very long process to legally put someone to death. There are of course Biblical stories about how that process was ignored (Jesus being the foremost example) but it highlights God's justice and His high view of human life. Not everything is easy to understand, especially in our society where we believe everything has to be done "our" way. One thing the Bible does show is that God works with people where they are. (John 16:12) He doesn't always shatter their world. He usually slowly molds it until it resembles the shape He wants. (Matt 19:8) This is true with individuals and then larger societies as well. I hope this helps you a little. Good question. I think all Christians should wrestle with this question.