[seodisparate]

[1] discusses firejail running as root:

> For a server, the process exposed to the outside world runs as an unprivileged user (unbound or nobody). The process is started by a separate process running as root (as explained by @Ferroin above). The starting process is never exposed to outside.

> The same is true for Firejail. By the time the unprivileged server process starts, Firejail is already sleeping.

And I think Docker has a similar problem as mentioned in the "warning" section in [2]:

> Warning: Anyone added to the docker group is root equivalent because they can use the docker run --privileged command to start containers with root privileges. For more information see [3] and [4].

[1]: https://github.com/netblue30/firejail/issues/1720

[2]: https://wiki.archlinux.org/title/Docker#Installation

[goodpoint]

Actually docker is much worse due to the large attack surface.