It is common to run more than one application in a given server. Nginx, for example, is widely used as a reverse proxy and web server for operating multiple containerized applications on the same server. Postgres is a commonly used database that can potentially be used on hundreds of applications simultaneously. Duplicating them on all containers would just create a mountain of problems and waste resources for no real benefit.

If all you’re running is lemmy then why are you so upset about containers “cluttering” up things? What is there to clutter up, your docker ps output ? If you want, just pretend the host is itself a container running lemmy (which it might just be, depending on your host!). Alternately, make your own nested container that just does a docker-compose up and pointlessly duplicate all the services you want. Complaining that the container managers don’t do this for you, to the detriment of others who don’t share your specific niche, is just blatantly entitled and absurd.