Xfce4-notifyd was built without support for your windowing system -- WSL

WSL is a stripped down Linux environment that allows you to boot up into an almost fully featured one, I’m not surprised it needs sudo, thats for the kex server to connect to the Linux environment and display over vnc

The whole point of WSL is that you are able to use Linux commands inside Windows Powershell.
Powershell has been released for most platforms now, even Linux!