It shows a bit more than that, at this moment some “guest” is looking at a members profile and another “guest” is looking at the De Kock post. Surely no one who isn’t a member should be able to look up a members profile?
This is definitely not a worry at all. There's loads of automated bots a crawlers scraping the content of the web for different reasons. Normally their activity is not noticed, but Xenforo displays activity of these in the sidebar widget. That's perhaps the reason why some users think this is bit of a worry, but it's definitely not. It' absolutely normal behavior happening on every site.