I never understood people acting like downvoting is some huge crime or being downvoted is some great slight. It's a little arrow on a web site. It makes a number in a database go up or down by 1. I don't care how many points my comments score, and neither should anyone else. Speak your mind, or don't, and move on with life.
It's not about scoring imaginary internet points, it's about deciding what is and isn't acceptable in our community. For me the bar for "unacceptable content" is a lot higher than just "dislike."
As others have mentioned, if I disagree and think it's worth the time to engage, I'll respond and hopefully we have a fruitful discussion. Like/dislike doesn't really come into it. If I really dislike it I just close the tab or ignore the comment.
I'd like to see a wider range of options that have different effects on a post/comment like specific agree/disagree buttons that don't have the effect of making the comment move up/down or be lighter/darker, maybe just shows a count for both agree and disagree, not a single number that moves up for agree and down for disagree like votes do. Flag-like reactions should require some type of write-up, single-click actions are too convenient for users in a rage.