Yeah, it certainly conflicts with https://fedoraproject.org/wiki/Packaging:Guidelines#Noarch_with_unported_dependencies

It seems to only supported method is ExcludeArch or making the package arch specific.

We discussed this at this weeks meeting (http://meetbot.fedoraproject.org/fedora-meeting-1/2016-01-14/fpc.2016-01-14-17.01.txt):

• 587 Node.js Guideline ExclusiveArch incorrect (geppetto, 17:06:36)

• That's just how koji works, noarch is needed for rpmbuild removing
  it doesn't fix the problem. Just have to resubmit until you get a
  correct arch. (geppetto, 17:22:16)
• ExcludeArch also doesn't do anything. FWIW. The only other option is
  to make the packages arch. (geppetto, 17:23:44)
• LINK: https://fedorahosted.org/koji/ticket/210 (orionp, 17:30:13)