Full agreement, Immich has a similar problem. I don't know at what point basic systemd services stopped being enough but docker is usually a non starter for me.
I dunno, I enjoy not having to install 500 libraries on my system just to test an app. Also upgrading those libraries without butchering my system is also nice. Not to mention rebuilding a system is really fast. Too many pros outweigh the cons
A developer must have had a working config at some point to create the Dockerfile. Providing literally only the Dockerfile is usually just a sign of throwing hands up and saying "It's too hard!".. you should be able to package for at least one platform that isn't Docker. That's just app development, or at least it was until recently.