I posted this reply via email, and on the web interface (which I use now) doesn’t allow one to emoji react to that message. One cannot 
it. Weird. That’s (IMO) a bug in discourse.
@nukeador could this be a solution for you for people who don’t want their messages voted on? For them to just use mailing list mode?
Update 2022-03-28: I was mistaken, it is possible to to this post