Let's be clear: people have the right to like or dislike what they want - that is why the option is there. As long as they are not doing it in a malicious way to retaliate or game the system, there is no policing the votes. If you get a down-vote, live with it. If you get up-votes, be happy. If you realize neither really matters ... be content.
If it is someone that wants to cause you angst by disliking your posts then making a big issue of it just reinforces it as a way to push your buttons - and would surely attract it more. Sometimes people are petty and if you've disagreed with them over something they think it's "clever" to go through your posts disliking them ... as though it achieves something. Oh dear, making a public issue of it shows them that it does.
But a less paranoid explanation is that sometimes people maybe click the wrong button by mistake or maybe don't even realize they have clicked on something or maybe, just maybe, someone actually legitimately decided they didn't like something for some reason and used the option available to indicate it.
It's silly to go off accusing people and causing bad feeling without any evidence, especially when the accusations are wrong.
I also see it as a form of passive aggressive bulling ... are people meant to question whether they should dislike button for fear of the storm it will create if they do? That's equally unacceptable.
So please don't do it. Don't complain about votes unless you are happy not to receive any likes either and, of course, to not cast any votes yourself (yes, it is an option), If you have genuine cause to believe that someone is targeting you (and I mean you are regularly down-voted even for innocuous posts) then let me know and I can look into it. Accusing people and taking threads off topic is not going to help.