Pretty lame response tbh

That's honestly a really bad response. The "cider2-bin" package on the AUR essentially just uses a bash script to unpack a .deb package, move some files around, and re-package it as .pkg.tar.gz which is all the .pacman file is. There's no reason they can't create their own bash script based on that and run it literally anywhere.

That being said, now that they're finally providing a flatpak that's probably the way to install it.