BSD derivative systems have a lot better isolation than mondern Linux systems. In fact, one Docker "port" for FreeBSD is an interface over their jails functionality and it can be difficult to tell uourr even in a jail at first. They all have a much richer history of supporting multi-user machines.

Linux's route to multi-user is a very different history with very different use cases. It's also got a much richer history around single user machines (and the performance, efficiency and support gains you get from focusing there).