Puzzles habrakarma

Recently, I am very surprised by the behavior of my habrakarma, more precisely, those people who raise or lower it to me. Judging by the unchanged number of voters, the same people change their opinion about me several times a week. And the strangest thing is that there seems to be no reason for such fluctuations.

I will give an example.
A few days ago I entered into a controversy with Habraredaktsii. The result was a drop in karma by 12 points (it was +10, it was -2). At the same time, only those who previously left a positive assessment have put the karminus. Yesterday's publication of two topics devoted to errors on Habré, brought me +6 points (it was -2, it became +4). Again, the number of voters has not changed.

Question: who are these people and what are their motives?