For other reasons, it is just as bad when using python from Homebrew on macOS where sudo isn't necessary. `pip install` will install modules in `/usr/local` where they will get mixed with Homebrew-provided python packages. I was hoping there would be a way to make `pip install --user` the default, but I couldn't figure it out the last time I checked.
This is exactly why you want to do all (as in 100%) of your python work in a virtual environment, so the packages are completely isolated in your ~/.virtualenvs/[ENVNAME]/lib/pythonx.x/site-packages.
Never, ever, do a pip install in your non virtualenv environment.