Why do we ignore and violate many of the teachings in the Bible?

The naive answer:

Jesus tells us that some old testament rules only apply to Jews. Christians can ignore those.

The problem with the naive answer:

It is not obvious what Old Testament laws are to be ignored and which should still be obeyed. Many Christians ignore many teachings of the New Testament also.

The scholar’s answer:

Many passages in the Bible are ambiguous. Many rules in the Bible were created to help create coherence among the tribes of Israel and distinguish them from foreigners. Such laws no longer applied once Christianity spread outside of the Jewish people. Furthermore, some rules were part of the culture of people thousands of years ago, and are no longer considered appropriate for our more evolved culture today.

Here are a few examples of ignored teachings:

Logically, we can conclude that most Christians realized some teachings in the Bible are faulty and don’t need to be followed. To follow all those teachings might make them feel outcast among their neighbors and friends and require them to give up things they value and enjoy. Many of the teachings of the Bible had value in creating a group culture for the Jews, but are unnecessary for that purpose today.

Some references for further research: