It has been this way since Photos has first been released in 2015, on all Apple platforms.
A Photos Library is a relational database with several views. The Library albums are providing a basic structure automatically, grouping the library according to commonly used criteria, the data of import, the capture date, the media kind, the location, the people, pets, and objects in the photo. This basic structure is created automatically, based on all items in the library. It cannot be modified by the users. We are supposed to build our own views of the library on top of these predefined albums - use the Library as the foundation for your own thematic albums. Create your own “My Recents” album, if you need an album, where you can remove photos from, that you have added to albums. Our own albums can be modified freely.