I just added public likes. Any visitor can like a post/reply.
No one wants to implement total anonymous posting. Too many potential issues.
But, letting a visitor like should be safer.
Since they would not have a username, they would not be added to the list of people who liked, just the counter would increase.
It would need to use a cookie to help prevent them from liking too much. I know there are ways around the cookie. But, it’s better than nothing.