but it took me TEN minutes to find this forum
You were very quick! 😁 Here is a list of all forums - the site map: https://discussions.apple.com/productsitemap.jspa
That will it make easier to find the correct forum the next time.
The reason for hiding the Photos for Mac forum among the system software is, that Photos is part of the system. It is installed and updated by system updates, just like Mail or Contacts. The Photos.app is just a wrapper for calls to system services. You can see that, when you look at the file size of Photos.app: it is just 56.4MB large, not larger than a single RAW image file. Apple's previous photo application "iPhoto" on the other hand has a whopping file size of 1.7GB. iPhoto has been sold separately from the AppStore, Photos is not.
iMovie is hidden in the iLife section, because iMovie used to be part of the iLife application bundle.
It would make it easier to find the correct forum, if the forums were grouped according to the category of the software - photo applications in one group, video applications in another group, etc. And not by the name of the name of an outdated software bundle or how they are installed. You may want to send feedback to Apple: Apple - Feedback