Lenovsky [1] filed a deletion request for atom-editor-bin [2]:
I don't see reason of maintaining precompiled binary from official
repository [1].
[1] https://www.archlinux.org/packages/community/x86_64/ atom/
[1] https://aur.archlinux.org/account/Lenovsky/
[2] https://aur.archlinux.org/pkgbase/atom-editor-bin/