The idea behind Docker is to reduce a container as much as possible to a single process and then manage that through Docker. The main problem with this approach is you can't wish the OS away as the vast majority of apps and tools expect a multi process environment and support for things like cron, logging, ssh, daemons. With Docker since you have none of this you have do everything via Docker from basic app configuration to deployment, networking, storage and orchestration.
LXC sidesteps that with a normal OS environment and is thus immediately and cleanly compatible all the apps and tools and any management and orchestration layers and be a drop in replacement for VMs.
If you want more info:
LXC
https://linuxcontainers.org
https://www.flockport.com
Docker
https://docs.docker.com
