I can't speak for the parent, but I rarely login to the same remote server twice and don't want to need to set things up and clean them up anytime I do. This is why I try to keep my stuff as close to vanilla as possible. If anything goes wrong on a server and someone sees I have a whole bunch of dot files to customize my config, it becomes a red herring that I have to spend time explaining away.

Sometimes I ssh into a server as a specific user (e.g. as the "app" user that is used to run a web app), sometimes only root is available (probably not best practice, but it's not like I can or want to fix it myself).

In any case it's not practical to carry your dotfiles everywhere you go. Changes are also a hassle to propagate

Because I'm not the owner of the remote host.