If you're only using docker for development to bundle things in a different OS base image then there's not that much need for paranoia. You probably would trust the other OS vendor with your host system too. Running docker without security may be perfectly fine in that case.
For random scripts from github running them in docker is mostly a precaution so they don't screw up your host system or some malicious dependency makes a low-effort attempt at exfiltrating your ~/.ssh dir or whatever. In that case it makes sense to understand the basics, e.g. not just running docker --privileged willy-nilly just because some README asks you to.
If you're running some PaaS container service where users can execute arbitrary code on shared hardware then you better have a full-time security engineer or two who will be paid to understanding all the details involved.
If you're only using docker for development to bundle things in a different OS base image then there's not that much need for paranoia. You probably would trust the other OS vendor with your host system too. Running docker without security may be perfectly fine in that case.
For random scripts from github running them in docker is mostly a precaution so they don't screw up your host system or some malicious dependency makes a low-effort attempt at exfiltrating your ~/.ssh dir or whatever. In that case it makes sense to understand the basics, e.g. not just running docker --privileged willy-nilly just because some README asks you to.
If you're running some PaaS container service where users can execute arbitrary code on shared hardware then you better have a full-time security engineer or two who will be paid to understanding all the details involved.