What is your program - Photoshop Elements or Premiere Elements, what version, on your Mac computer?
If Photoshop Elements is your program, you have posted in the wrong forum. Somehow your thread got posted in the Adobe Premiere Elements Forum.
If Photoshop Elements - Elements Organizer, please re-post your thread in the Adobe Photoshop Elements Forum
Oops. I think I did post in wrong forum. I have Adobe Photoshop Elements 13, running on an iMac with Yosemite 10.10.4. I also have Adobe Premier Elements, which I also cannot access my Photos library. Import -> Files folders; Photos is greyed out.
Thanks for the follow up.
Photoshop Elements 13 and Premiere Elements 13 are standalone products, each having the Elements Organizer 13.
When they are on the same computer, they share the same Elements Organizer 13.
Since you have both programs, I see it appropriate for you to post this question in either forum. But in all practicality, you are likely to get your Mac Elements Organizer - Photos answer in the Adobe Photoshop Elements Forum with experts like Barbara Brundage.
My initial impression is that Mac's Photos does not yet have full integration opportunities.