All those libs are required by a lot of binaries from the FreeBSD-runtime
package, it make no sense to create a special package for them.
I explained the reasoning for runtime package in https://lists.freebsd.org/pipermail/freebsd-current/2019-April/073209.html. I do not think that increasing the size of the package just because it is convenient is reasonable. If you want all other (non-C-runtime) libs in one package, create it, but keep runtime package for its purpose.
There was a lot of things non related to runtime in the FreeBSD-runtime package which I'm slowly moving out (wpa, bluetooth and hostapd is done) but I did this move before this, I think I'll continue to move things out of the runtime package when it don't make sense and I will probably create a FreeBSD-libs (or whatever the name) to include all those.