I'll try to make this simple:
Apple supports the Unicode standard for encoding characters stored on iOS and macOS, because, frankly, using any other coding system would be insane (the entire world has moved to Unicode for good reasons).
The
Unicode Consortium has a group that is responsible for approving the addition of new characters and character sets to the Unicode standard, and
they keep accepting new emoji characters.
Apple,
in order to comply with the Unicode standard, has a few graphic artists (not software developers) design new images to go with the newly assigned emoji (and other characters). (Note also that small images are highly unlikely to break other software on the system, so such changes are comparatively easy to push through, unlike many of the more complicated software bugs.)
Apple publishes software (like this beta) that includes the new symbols (amongst
many other changes) in order to keep abreast of the standards, and they don't particularly publicize the new emoji, those usually get little more than a bullet point buried in the release notes.
News/rumors sites (
which you are reading of your own volition) like MacRumors (
not Apple), publicize the new Unicode characters added, and, predictably, such articles get a huge number of hits by people eager to complain about new emoji in iOS/macOS.
If you want to complain, complain
directly to the
Unicode Consortium about how they should stop adding new emoji to the Unicode character set, and/or complain
directly to MacRumors (not on page 5 of the comments, but write directly to the site's owners, their email addresses are at the bottom of the site's front page) about how much coverage they give to new emoji added to Apple's OS's. Complaining about it on page 5 of the comments here only makes you feel good.