From Fedora Project Wiki
It's often handy to use the pattern find ...|xargs and both find and xargs come from package findutils.
If this pattern is used by a Fedora maintainer in their spec file, it might be annoying to add the Buildrequires tag. But that's not the main point.
The point is that this pattern might be used somewhere in the makefiles, of in the configure script. If find or xargs is not available, it is probable that the build will produce broken rpms, without sufficiently visible error messages. To prevent this kind of problem, the maintainer would have to inspect every new upstream release whether it uses find or not. It's much better to simply guarantee that there commands are always available.