I honestly hate the downvote system because user just use it for disagreement. I don't know about other place, but sometime you get punished because you got too many downvote in a Reddit sub or sometime you get point off for getting downvoted in many other forum.
You obviously welcome to upvote for post that you like, but if you just downvote because you disagree a comment, It is just disguising how people can't accept other opinion. You can comment your disagreement under other's comment, but not downvote.
Or people just downvote because:
I am hater of X and I want to down any X praise from people.
Or
I think in this controversy people should be on this side, and if you think other I'm gonna downvote you.
If people said something that is toxic, hate or that is against the rule. You can simply report them and the mods should do appropriate action if something is reported.
Conclusion, I think the downvote system is unnecessary because people simply downvote other with their disagreement. If some opinion were crossing over the line, they should be report them and mods should do appropriate action to ban/punish the users.