Indeed, the expression "Code of Conduct" may sound a bit scary. Nevertheless, its purpose is to prevent (potential & actual) participants from being scared to join. The Berlin Code of Conduct*, based on the work of the Ruby community, puts it this way:
"A primary goal of all the conferences and user groups that refer to this Code of Conduct is to be inclusive to the largest number of contributors, with the most varied and diverse backgrounds possible. As such, we are committed to providing a friendly, safe and welcoming environment for all, regardless of gender, sexual orientation, ability, ethnicity, socioeconomic status and religion (or lack thereof). This Code of Conduct outlines our expectations for all those who participate in our community, as well as the consequences for unacceptable behavior. We invite all those who participate in our events to help us create safe and positive experiences for everyone."
You can find the Berlin Code of Conduct here
It turns out what feels neutral to someone can be threatening or hurtful and inappropriate for another with a different background. Agreeing to such rules upfront brings the crowd on board, so the event is enjoyable for everyone behaving professionally and respectfully.
*Berlin Code of Conduct is distributed under a Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.