Pretty much par for the course, Linux distributions don't do per user configuration of tools beyond appending to PATH or setting some essential environment variables using scripts in in /etc/profile.d/. They will most certainly not mess with login scripts.
Yeah sure, that makes sense. I'm surprised that the .deb doesn't install the stuff from `$upstream/shell` into `/usr/share/fzf` though. That's the sort of thing `/usr/share/$prog` is intended for.