I would like to suggest a UX improvement from my own experience with the plugin.
I go to a thread page while logged out, such as Hints, Tips and Tricks - Support - OpenRefine
I hover the reaction button on the first post of that thread, wanting to add a reaction to the post.
While hovering this button I see the message “You can no longer remove your like”
This message is not appropriate: I have not added a like to that post yet, so I cannot want to remove it. It should rather indicate that I cannot add a like because I am logged out.
Looking at the code, the same message is currently displayed regardless of the reason why the user cannot add a reaction.