Believe it or not, you can! Check our the documentation https://coralproject.github.io/talk/ where you can use plugins to hook any any part of the commenting process.
[1]: https://coralproject.github.io/talk/docs/plugins/server/
Your best bet if you really want this feature is to implement it yourself server-side with just enough knobs to make it useful for your user-local case, and hope that other sites agree...
I.e. as I upvote your comment, I publish the info that "user XYZ upvoted this comment" which you can use in your own user-local moderation schema (at your discretion).
What we have to avoid is when Potential Employer looks for info on "John Q. Smith", they can identify which articles he upvoted.