Gnome doesn't allow other applications to access its private API

This seems perfectly fine.

Private APIs are private and shouldn't be used by third-party, specially if it can bypass security measures [1], furthermore, they've a working alternative already: the portal system.

As a side note, this will break the hackish screen sharing implementation that Zoom has made for GNOME on Wayland and might force them to update to the standardized portal system that works anywhere.

[1] https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3943

And this has made flameshot not able to work under Gnome: https://github.com/flameshot-org/flameshot/issues/1910