Just make it easy: compare THIS Firewall-Setting with any other Firewall-setting (service) running on your computer which is allowed to connect to anywhere.
If you don´t belive me, just check every other manual defined firewall settings (not the Microsoft predifined because in those the settings are greyed out and can´t be changed) and see the settings on all the other programs.
Like if you have iTunes installed, check the firewall setting of iTunes (the Services: Apply to...)
What you're suggesting is to take this rule and apply it to every service on the computer, so that any kind of incoming connection is allowed to reach every service on the computer. I don't want to do that
This setting means: You can define what local running program or service can connect to that specifc firewall defined program. In that case, if you want to connect from ext. (which means another computer) to this in the firewall defined programm (in that case is the Glasswire Service), you must in the service section select "Apply to all". If you select you want only allow one specific service to connect to THAT Glasswire service, then you can select that service.
Make it easier: You have a program A ... and you create a firewall rule for program A. In that firewall rule for program A you can even specify if only a program or a windows service is allowed to connect to program A. It is an inbound connection. So if you want to connect to that program A from an external computer, you must change the settings for the program A specifc firewall setting.