Here’s the situation:
Opening a Private Window w/Tor - Right now, you’re unable to launch a tor window from the get-go. We have an issue to add this option to the context menu in future updates. The one exception is editing file paths to launch with flags (note: I’m actually not sure how to do this in macOS or if you can - you may need to do it strictly from Terminal).
For example, on Windows, if you navigate to your Brave shortcut,
right-click --> Properties --> Target, you’ll see a path string like:
If you append
--incognito to the path, every time you use that shortcut, Brave will launch in a private window.
This is what it looks like when Brave has an update ready for you. It will display as that green arrow until the browser is update, at which point it will revert to the “hamburger” menu:
You should see the option for all window types there:
Edit: Forgot to answer your original question - I believe its for security reasons that you open a new Tor window instead of standard window while inside private w/tor. Much of the goal with Tor and Private windows is to ensure that Private, Private w/Tor, and standard windows are all easily distinguishable and don’t get mistaken for one another.