I admit it is confusing. LXC typically means the lxc-* commands like lxc-start and so on. That's the daemon-less "old way". The links the grandparent provided was to this, and their complaint is about that stuff that is in maintenance mode and not actively developed any more.

LXD is a complete rewrite. There is now a server daemon called "lxd", and the client for that is "lxc".