Somewhat of a special setup, I'm reposyncing all the ppc64 packages from the ppc64 secondary arch, and then bringing in all the noarch packages from the x86_64 repo. Long story.
For the ppc64 run I have a repo set up that has exclude=*.noarch and for the x86_64 noarch run I have a exclude that looks like *.x86_64,*.i?86 so that it'll just grab noarch.
When I run reposync with -d it seems to delete everything that doesn't match the unexcluded package set, which means when I did that for ppc64 I lost all my previously downloaded noarch packages (all 7300 of them). For now I'm running without -d but that means I'll have a growing storage problem.
It'd be cool if there was an option in reposync to not delete the excluded packages. Don't know how feasible that is, or how specialized my case is, but here ya go anyway.
yum and related packages are no longer actively developed.
They are being replaced with dnf, dnf-utils, etc.
I'm closing this bug because it's most likely never going to be fixed.
If you still consider your bug report important, reopen it, please.