Ratione from my colleague Carlos O'Donell:
"The intent of this patch is to remove the default search paths of the dynamic loader from DT_RPATH/DT_RUNPATH. This allows the default system paths to be searched last as is expected by most programs, and enables LD_LIBRARY_PATH and cache searches to happen first. The patch does not forbid rpath in any form, but forbids promoting default system search paths in this way."

He added:

If you allow the default library paths in rpath, it bypasses the usual hierarchy of checks -> (a) DT_RPATH -> (b) LD_LIBRARY_PATH -> (c) DT_RUNPATH -> (d) cache -> (e) system defaults. Allowing /usr/lib64 in DT_RPATH moves that path from (e) -> (a). In terms of a search hierarchy.

It's not really the behaviour you want in the [Fedora/RHEL] distribution, you want the system defaults to be at the end of the search order instead of being promoted to early searches. The intent of the patch should be documented as such so we remember why we made the change. It's the same problem as adding /usr/lib64 to LD_LIBRARY_PATH, which on RHEL7 actually has a bug in some cases which can lead to crash.