I’m confused by your post.

1. theirs is a reaction to someone posting a cartoon as a comment.

2. they give a link to the original. (And before you say that that post had to have been edited to add the link, it would be marked as such, like this one, and it doesn’t show that the post is edited)

3. anyone can see those comments. It’s not limited to just the poster, unless you’re not on Lemmy, but instead are viewing this thread from someplace else in the fediverse, like Mastodon.