Devil's advocate here: Do they though? Are you contributing anything of value in a conversation medium when you decide to indicate "confused!" or "sad!"? Are they vehicles for abuse or harassment?
Contextual responses are important, and "I agree with everything you said" is a shortcut that works and is largely free of malicious intent (it's hard to "I agree with you" in a way that is offensive to the person authoring the remark), however the ability to react negatively to content without stating why in a medium that encourages exchange is at odds with the platform in some use cases.
I think it's great that IPS has the easy, built in ability to define reactions for each and every install and that administrators are able to sort out what works best for their individual communities. I also think that for some communities, like this meta one, it's important that the balance of opinions, the dissenting expressions and thoughts, and that the less than positive reactions to content be fleshed out with words and quotations over a wordless reaction. That 4 people were confused about a post doesn't help the author of that post (or the people working on this platform) understand what was confusing, nor provide context to clarify.
By removing shortcuts that add little value (in this case, negative reactions), you need to express those things verbosely, and for many communities (and for this community), I think that's a better thing than the alternative.
If you disagree with me, you're encouraged to reply how and why and we move the conversation forward.