I have two suggestions for how they could be changed.
a) Don't display "dislike" and "disagree" reactions in the avatar beside every forums post. There's nothing wrong with disagreeing with a post, but it shouldn't be on your record forever, especially since every now and then people will react to every post with "dislike" because they don't like the poster (for example).
b) Remove the "dislike" reaction (keep "disagree") and replace it with "neutral" or "confused." Often there will be something that I'm not sure I understand properly, and I'll want to react to it in some way, but a negative reaction seems harsh. A "confused" reaction would be a great addition.
I don't know if the forums host supports this, but if it does this would be great to see!