Docker group membership is more dangerous than sudo
https://docs.docker.com/engine/install/debian/
The Docker daemon has setUID root, and by design allows easy access as root to the host filesystem. This makes it trivial for a malicious user to read and alter sensitive system files, or for a careless user to allow a malicious containerized app to do so. Access to Docker commands effectively grants full root power.
Also, Docker doesn't have any equivalent to sudo's password check, which means that a successful arbitrary-code-execution exploit against a user who is in the docker group effectively grants the attacker root. Thus, the safer choice is to never add a user account — even your own — to the docker group, so that Docker commands can only be used via sudo.
