That is something that has already been talked about on several occasions. Knowing who gives karma (especially the negative one) will never be a good idea, as that would lead to many arguments, tensions between users, and wars that would never end, and that would be creating an atmosphere totally opposite to what should exist in the forum.
Sending Karma (positive and negative) will remain anonymous, otherwise, we would all end up crazy.
The current system is certainly not the best solution.
So, for example, I get negative karma points every day, even when I'm inactive for a few days. I assume it comes from the same user, because it happens daily, probably after the limit expires.
Earlier, I presented a few cases of spammers, so maybe it's some kind of punishment for me for ruining someone's multi-account business.
Now from my point of view, I would rather say that it is unfair that one can covertly give negative karma, because that way the real intentions are concealed, than that unnecessary "drama" would cause harm.
If I am right in my case, then it is certainly not stimulating to work on improving the forum.
It might be good to know that the admin, as part of regular maintenance, periodically checks the karma log to prevent misuse.