There are a number of packages in the tree where servers and clients are conflated into a single
package, and the servers are uncommonly used or sometimes actually insecure. Specifically, I'm
thinking of netkit-fingerd and telnet-bsd.
Furthermore, there are alternative fingerds out there that check for the presence of the finger(1) binary
during compile; the netkit finger is perfectly servicable as a client, but installs a rather icky fingerd.
It would be really nice if an option (probably a USE flag?) could be added to gentoo signifying that those
"optional" servers should not be installed. I've written hacked ebuilds that do this for my own machine,
but a standard solution to this probably common desire would be nice.
This has been discussed a while ago and the tenor was that we have not nearly
the ressources (dev time) to do this. Especially the two packages you mention
have not even a maintainer for example.