I just noticed the following inconsistency: the pam_ck_connector module manpage states:
“This PAM module should be used with caution; only local
login managers such as login(1) should use this.”
So I'd have expected it to be used in LOCAL PAM configurations. However, it apparently is used for remote sessions as well: it is included in system-login, which gets included both from system-remote-login and system-local-login. This seems like a bug to me: judging from the manual (and this kind of makes sense if you want to decide whether someone controls the console), I'd expect this module to only go into system-local-login. Sure, I can reconfigure this locally, but others probably won't inspect their PAM config and still expect sane defaults.
If there is indeed a reason why the configuration should be different by default, then that fact should perhaps be documented somewhere, e.g. in a comment line in that configuration file. And if that reason is not specific to Gentoo, then it might make sense to contact upstream about it, and request a suitable change to the man page.
consolekit support was removed in 20200804