I believe there are reasons. I think Podman was developed to overcome some of the failings of docker design, but be a drop in replacement for Docker using the same commands and I think connecting to the same repositories too (but not sure about that). I believe since Fedora attempts to be closer to the bleeding edge of technology they disabled older CGroups (I know so little, I’m not really sure what this is) and so Docker doesn’t run on Fedora 32 and later out of the box. Here is an article on the topic Docker and Fedora 32 - Fedora Magazine
I believe you can’t install Podman (without adding extra repos) to Debian Stable, but this is due to the fact that Podman wasn’t to a point of stability that it could make it into the last Debian stable. However, it looks like Podman is in Bullseye, current testing branch, and next stable release.
I can’t find LXD in any Debian repos. I wonder if LXD is so Ubuntu specific that you can’t run it without snapd on other systems because it needs something that only Ubuntu has.
As I mentioned, exploring some of these differences and shedding a little light on the container world would be a neat video that I think Jay would do a great job with since he seems familiar with all the pieces of the puzzle. You are right @Buffy as far as trying them, I’ve got the homelab hardware to spin up an Ubuntu server and poke at it. I was more interested Jay’s view of the systems. For right now, I’m content learning and playing with Docker in my homelab using Jay’s video series that he has already published.