I think it was a "removing from future versions of macOS" situation, not removing from existing installs. If your mac is old enough to not have homebrew, it's probably too old to install Catalina due to the fact that they stopped supporting devices without Metal support.
Also, feel free to replace `brew install emacs` with the macports equivalent and the point still stands.
Well sure, there are alternatives. I was commenting on the casual assumption that everyone has brew. Brew has worse support for older Macs than a lot of other software.
Also, feel free to replace `brew install emacs` with the macports equivalent and the point still stands.