If you are not aware, this site runs on the open and free software Discourse.
Since this site is hosted for free by the company Discourse, the site is limited in what plug-ins it can use.
There is one plug-in that might become available for use on free Discourse hosted sites and is being tested on the Discourse public meta server this week.
Notice: testing Discourse Reactions here on meta for 1 week!
At present if it does become available for this site I plan to enable it and see how it works here.
Also, having been a member of sites such as StackOverflow that allow for down votes and Discourse that does not allow for negative reactions, I don’t plan to allow negative reactions with this plug-in. Constructive and useful feedback for the community is welcome in the topics but negative feedback is not. In other words it you can not say something useful and constructive for the community then please don’t say anything or give a negative reaction. 
If an OP seeks some form of negative reaction, think voting by reaction icons but not negative text, and if the OP notes it in the original post then as an admin I will refrain from removing the negative reactions or getting involved.
EDIT
From: Sam Saffron one of the Discourse co-founders
Multiple reactions is sadly not on our roadmap, it is a completely different UI with very different constraints.
(ref)
We are discussing this internally, we certainly expect it to be available on teams and enterprise, but are also deciding about business/standard tiers
We will make an announcement here once decided
We still have some in progress work, I expect about one month till our official announcement
(ref)
FYI This site is considered a standard tier site.